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Tytuł:
Second-Order Phase Transitions in Magnetic Ca₃Al₂(SiO₄)(Oₕ¹⁰) and Non Magnetic Cubic ZnO
Autorzy:
Kunert, H.
Powiązania:
https://bibliotekanauki.pl/articles/1386491.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
Possible symmetry of modes those may cause transitions in magnetic and non magnetic crystals as well as lower space subgroup symmetries of the crystals have been found. The Landau-Lifshitz theory for non magnetic crystals has been reformulated for magnetic crystals and has been applied to Ca₃Al₂(SiO₄)(Oₕ¹⁰). Some experimental data confirm our results.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 439-441
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect-Related Origin of the Ferromagnetism in ZnO:Co
Autorzy:
Hanafin, R.
Pemmaraju, C.
Archer, T.
Sanvito, S.
Powiązania:
https://bibliotekanauki.pl/articles/1810514.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
In recent years transition metal ion doped ZnO has been the focus of intense scientific enquiry. ZnO:Co is by far the most studied member of this family. However, despite the many experimental claims for ferromagnetism, a definitive theoretical explanation for long range magnetic interaction has so far been lacking. Here we present a mechanism which describes not only the origin of this previously inexplicable magnetism but also explains the experimental findings to date and in addition, suggests a recipe for tailoring the magnetic properties. We demonstrate that the magnetism originates from a $Co^{2+}$ oxygen vacancy pair with a partially filled level close to the ZnO conduction band minimum. The long range coupling then occurs via conduction electrons at moderate n doping. This however is not sufficient for room temperature ferromagnetism due to the prohibitive concentrations of O vacancies needed. The experimental findings may then be explained by a combination of our proposed mechanism and the formation of blocked superparamagnetic clusters.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 263-265
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of EuS/PbS Semiconducting Structures
Autorzy:
Stachow-Wójcik, A.
Twardowski, A.
Story, T.
Dobrowolski, W.
Grodzicka, E.
Sipatow, A.
Powiązania:
https://bibliotekanauki.pl/articles/1968421.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
We report results of magnetization study of EuS/PbS superstructures with different thicknesses of magnetic and nonmagnetic layers. Reduction of ferromagnetic phase transition temperature was found with decreasing EuS thickness. Reasonable description of this effect is obtained within the model based on the mean field approximation.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 985-988
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of the Energy Gap in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se
Autorzy:
Gaj, J. A.
Nguyen, The Khoi
Arciszewska, M.
Lebecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/1891022.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
The energy gap and magnetic susceptibility of Cd$\text{}_{0.85}$Fe$\text{}_{0.15}$Se were measured in function of temperature. Experiments showed that the magnetic contribution to the variation of the energy gap in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se is not proportional to the product of magnetic susceptibility and temperature as it has been observed in Mn$\text{}^{++}$-containing semiconductors.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 405-407
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Susceptibility and Charge State of Gd Impurity in Pb$\text{}_{1-x}$Sn$\text{}_{x}$Te⟨Gd⟩ Crystals
Autorzy:
Zayachuk, D. M.
Ivanchuk, R. D.
Kempnyk, V. I.
Mikityuk, V. I.
Powiązania:
https://bibliotekanauki.pl/articles/1952432.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
The effective magnetic momentum p$\text{}_{eff}$ of Gd-impurities in the Pb$\text{}_{1-x}$Sn$\text{}_{x}$Te⟨Gd⟩ crystals as a function of crystal composition x with 0 ≤ x ≤ 0.25 is studied. It is shown that with the increase in tin content in the crystals from 0 to 0.15, p$\text{}_{eff}^{2}$(Gd) increases slowly from 37 to 43. Then p$\text{}_{eff}^{2}$(Gd) increases abruptly to 63 value when x = 0.16±0.01. For subsequent increase x ≥ 0.17 p$\text{}_{eff}^{2}$(Gd) remains constant at 63. Possible reasons of observed changes of p$\text{}_{eff}$(Gd) and possible mechanisms of influence of the Pb$\text{}_{1-x}$Sn$\text{}_{x}$Te crystal field on the effective magnetic momentum value of Gd-impurities in the crystals under study are analysed.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 985-988
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Photoluminescence Study in PbS-EuS Superlattices
Autorzy:
Kowalczyk, L.
Sadowski, J.
Gałązka, R. R.
Stachow-Wójcik, A.
Sipatov, A. Yu.
Volobuev, V. V.
Smirnov, V. A.
Dugaev, V. K.
Powiązania:
https://bibliotekanauki.pl/articles/1991612.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
Investigations of the photoluminescence of PbS-EuS superlattices deposited on (111)BaF$\text{}_{2}$ substrates are presented. Quantum-size and deformation effects in photoluminescence spectra are observed. The strain-induced gap shift and valence-band offset is determined from experimental results. A strong stimulated photoluminescence with relatively low threshold was observed. It was found that the photocarriers generated in EuS barrier strongly affect the population of PbS subbands.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 397-400
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Faraday Rotation and Photoionization of ZnCrSe Semimagnetic Semiconductor
Autorzy:
Mac, W.
Nguyen, The Khoi
Gaj, J. A.
Twardowski, A.
Demianiuk, M.
Stachow-Uciakowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1929663.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
The magnetoabsorption and the Faraday rotation of ZnCrSe were measured for B ≤ 5 T and T = 2 K in the region of photon energies lower than the fundamental absorption edge. The circular dichroism of the photoionization absorption bane was observed and analyzed. The Faraday rotation was interpreted as due to the sum of contributions from interband and photoionization optical transitions.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 567-570
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Interaction in ZnCrSe Semimagnetic Semiconductor
Autorzy:
Mac, W.
Nguyen, The Khoi
Twardowski, A.
Gaj, J. A.
Demianiuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1924249.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
Magnetoreflectance and magnetization of ZnCrSe were measured for B ≤ 5 T and T = 2 K. A linear dependence between exciton splitting and magnetization was found. The s, p-d exchange parameter was estimated: N$\text{}_{0}$α-N$\text{}_{0}$β=0.67eV.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 902-904
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Temperature Ferromagnetism and Nano-Scale Phase Separations in Diluted Magnetic Semiconductors and Oxides
Autorzy:
Dietl, T.
Powiązania:
https://bibliotekanauki.pl/articles/2047208.pdf
Data publikacji:
2007-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
In this paper the present understanding of the origin of ferromagnetic response that has been detected in a number of diluted magnetic semiconductors and diluted magnetic oxides at room temperature is outlined. It is argued that in these systems, owing to a typically small solubility of magnetic ions, crystallographic or chemical phase separation into regions with a large and a small concentration of magnetic component takes place. The ferromagnetic signatures then come from the regions with a large concentration of magnetic ions, which show non-zero spontaneous magnetization up to the blocking temperature, whose magnitude is proportional to the nanocrystal volume and magnetic anisotropy. Novel methods enabling a control of nano-assembling of magnetic nanocrystals in non-conducting matrices as well as possible functionalities of these spatially modulated magnetic systems are described. We also discuss phase separations into paramagnetic and ferromagnetic regions, which are driven by the Anderson-Mott localization and/or competing ferromagnetic and antiferromagnetic interactions. Finally, the question whether the high temperature ferromagnetism is possible in materials without magnetic ions is addressed.
Źródło:
Acta Physica Polonica A; 2007, 111, 1; 27-46
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Direct Measurements of Bound Magnetic Polaron Magnetization in Ga-Doped Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
Autorzy:
Stankiewicz, J.
Palacio, F.
Villuendas, F.
Powiązania:
https://bibliotekanauki.pl/articles/1968418.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
Light induced remanent changes in magnetization of n-type Cd$\text{}_{1-x}$Mn$\text{}_{x}$ Te (x=0.01, 0.05) single crystals have been measured at T=2 and 5 K and in magnetic fields of up 0.5 T. The effect observed gradually saturates with increasing magnetic field. It also correlates with light induced increase in shallow donor concentration measured on the same samples. The bound magnetic polaron theory accounts for the temperature and magnetic field variations of the persistent magnetization. There are no fitting parameters.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 976-980
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Epitaxial (Ge,Mn)Te Thin Films with Varying Crystal Stoichiometry
Autorzy:
Knoff, W.
Domukhovski, V.
Dybko, K.
Dziawa, P.
Górska, M.
Jakieła, R.
Łusakowska, E.
Taliashvili, B.
Story, T.
Reszka, A.
Anderson, J.
Rotundu, C.
Powiązania:
https://bibliotekanauki.pl/articles/1811940.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
Magnetization of 1 μm thick ferromagnetic IV-VI (Ge, Mn)Te semiconductor layers with 10 at.% of Mn was studied by SQUID magnetometry method up to the magnetic fields of 70 kOe. The layers were grown on BaF₂ (111) substrates by molecular beam epitaxy with varying Te molecular flux, which permitted the control of layer stoichiometry and conducting hole concentration. X-ray diffraction and in situ electron diffraction characterization of layer growth and crystal structure revealed two-dimensional mode of growth and monocrystalline rhombohedral crystal structure of (Ge, Mn)Te layers. Controlling the layer stoichiometry influences the temperature dependence of magnetization with the ferromagnetic Curie temperature varying in $Ge_{0.9}Mn_{0.1}Te$ layers from $T_c$=30 K (low Te flux) to $T_c$=42 K (high Te flux).
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1159-1165
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second-Order Phase Transitions in Non-Magnetic Wurtzite ZnO and Magnetic Doped with Co
Autorzy:
Kunert, H.
Niyongabo, P.
Powiązania:
https://bibliotekanauki.pl/articles/1385751.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
We investigate the second-order phase transitions in non-magnetic wurtzite ZnO and magnetic doped with cobalt. Using reformulated Landau-Lifshitz theory of second-order phase transitions and our computer program, we have found all possible lower space group symmetries of ZnO and ZnO doped with Co as well as symmetries of vibration modes which may cause structural phase transitions. We interpret the Raman phonon modes of magnetic doped ZnO according to corepresentations of the magnetic space group P6'₃m'c (ZnO magnetic). Some experimental techniques like X-ray diffraction, reflectivities and Raman spectroscopies can verify our theoretical results.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 400-403
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Specific Heat Study of the Competition between Ferro- and Antiferromagnetic Spin-Spin exchange Interactions in PbSnMnTe
Autorzy:
Łazarczyk, P.
Jędrzejczak, A.
Story, T.
Arciszewska, M.
Gałązka, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/1952041.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Lk
Opis:
Magnetic contribution to the specific heat, magnetic susceptibility and Hall effect are experimentally studied in Pb$\text{}_{1-x-y}$Sn$\text{}_{y}$Mn$\text{}_{x}$Te semimagnetic semiconductors with y=0.72 and x=0.08 and with different carrier concentrations 10$\text{}^{20}$ ≤ p ≤ 10$\text{}^{21}$ cm$\text{}^{-3}$. The ferromagnetism observed in crystals with p ≥ 3×10$\text{}^{20}$ cm$\text{}^{-3}$ breaks down with a decreasing concentration of carriers due to an increasing competition between Ruderman-Kittel-Kasuya-Yoshida and superexchange interactions.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 891-894
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Spin-Glass Phase Formation on Exciton Magnetic Polaron in (Cd,Mn)Te
Autorzy:
Chudnovskiy, A.L.
Rosenow, B.
Oppermann, R.
Yakovlev, D. R.
Zehnder, U.
Ossau, W.
Powiązania:
https://bibliotekanauki.pl/articles/1950742.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Lk
75.50.Pp
Opis:
The influence of the spin-glass phase formation of the (Cd,Mn)Te semimagnetic layers on properties of the exciton magnetic polaron were investigated both theoretically and experimentally. The theoretical model offers a consistent description of the temperature dependence of the exciton magnetic polaron energy in the vicinity of spin-glass transition and shows good agreement with the experimental data.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 755-758
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concentration Dependence of Photo-Induced Magnetization in Diluted Magnetic Semiconductor Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
Autorzy:
Yamaguchi, Y.
Kawai, H.
Sato, T.
Powiązania:
https://bibliotekanauki.pl/articles/1956517.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Lk
75.50.Pp
Opis:
The photo-induced decrease in magnetization ΔM$\text{}_{photo}$ was observed in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te (0.25 < x < 0.42) under unpolarized light illumination whose photon energy is smaller than the band gap of the sample. The photo-induced magnetization decreases with increasing Mn content through Mn$\text{}^{2+}$-Mn$\text{}^{2+}$ antiferromagnetic interaction, which supports our idea for origin of it based on the flipping of Mn spins in the bound magnetic polarons accompanied by the spin-flip Raman scattering.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 479-482
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conductivity and Magnetism of Magnetic Oxides
Autorzy:
Gehring, G. A.
Powiązania:
https://bibliotekanauki.pl/articles/2012877.pdf
Data publikacji:
2000-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Gg
Opis:
In a stoichiometric oxide the energy for the magnetic ordering is due to superexchange. This depends on the virtual transfer of a d electron from the transition ion to the neighbouring oxygen. When the oxide is p-doped there are compensating holes on the oxygen or the transition ion becomes mixed valent. The oxide may then conduct. The same transfer integral enters both the expression for the antiferromagnetic superexchange and the band width of the mobile carriers. Thus materials with a large antiferromagnetic exchange energy will be expected to have a relatively wide conduction band in the doped state and hence to have a high conductivity. In this paper the difference is explored between the materials in which there is true antiferromagnetism and those which are ferrimagnetic. In the antiferromagnets the carriers must destroy the magnetic order as they move. This behaviour is well known from the cuprates. In ferrimagnets the carriers may be able to move entirely on one sublattice. This occurs in Fe$\text{}_{3}$O$\text{}_{4}$ and probably in the doped garnets. In the case where motion is on one sublattice then doping does not destroy the magnetism and there is a relatively small magnetoresistance. An interesting feature is that unlike the cuprates the ferrimagnets do not become good metals at any doping but exhibit hopping conductivity. We explain the apparent paradox that the best conductivity is actually observed in materials where the conduction is only allowed when the antiferromagnetism has been quenched and that the conductivity in ferrimagnets is low.
Źródło:
Acta Physica Polonica A; 2000, 97, 1; 175-184
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Susceptibility of PbSnMnTe in the Transition Region between Ferromagnetic and Spin Glass Phase
Autorzy:
Story, T.
Gałązka, R. R.
Eggenkamp, P. J. T.
Swagten, H. J. M.
de Jonge, W. J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1920980.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Lk
Opis:
The ac magnetic susceptibility (χ) was measured in the temperature range T = (1.5÷50) K for Pb$\text{}_{1-x-y}$Sn$\text{}_{y}$Mn$\text{}_{x}$Te samples with a composition y = 0.72, x = 0.015÷0.04 and carrier concentrations in the range p = (2.85÷14) × 10$\text{}^{20}$ cm$\text{}^{-3}$. The breakdown of ferromagnetism and the formation of a spin glass phase are observed with an increasing carrier concentration. It is experimentally evidenced as continuous deviation of χ(T) from the characteristic critical behavior observed for ferromagnetic samples.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 630-633
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and Magnetic Properties of Pb$\text{}_{1-x-y}$Sn$\text{}_{y}$Mn$\text{}_{x}$Te (x ≤ 0.16)
Autorzy:
Łazarczyk, P.
Grodzicka, E.
Arciszewska, M.
Witkowska, B.
Dynowska, E.
Miotkowska, S.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/1876221.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Lk
Opis:
Hall constant, conductivity and magnetic susceptibility of Pb$\text{}_{1-x-y}$Sn$\text{}_{y}$Mn$\text{}_{x}$Te semimagnetic semiconductor were investigated as a function of Mn content (x = 0.04, 0.09, 0.16, y = (0.7-0.8)) in the temperature range T = (4 - 300) K. A ferromagnetic phase transition takes place at T = 5 K for samples with x = 0.04, at T = 10 K for x = 0.09 and at T = 20 K for x = 0.16. For crystals with x ≥ 0.09 the strong temperature dependence of the Hall constant is observed for temperatures below 40 K. Magnetic field characteristics of the Hall effect is strongly non-linear at T = 4.2 K. No significant temperature or magnetic field dependence of conductivity is observed in the whole temperature range studied. The observed transport anomalies are due to the anomalous Hall effect.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 469-472
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Epitaxial Strain on Magnetic Anisotropy in (Ga,Mn)As
Autorzy:
Juszyński, P.
Wasik, D.
Gryglas-Borysiewicz, M.
Przybytek, J.
Szczytko, J.
Twardowski, A.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1403622.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.47.-m
Opis:
Two (Ga,Mn)As samples having different magnetic anisotropy (one with in-plane easy axis and another one with out-of-plane easy axis) were studied by means of magnetotransport experiments. Anisotropy field B_{A} was determined for both samples as a function of temperature. For the sample having in-plane easy axis, an inversion of the direction of planar Hall effect hysteresis was observed upon increase of temperature. This result was simulated using the Stoner-Wohlfarth model.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1004-1006
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static and Dynamic Spin Organization in Magnetic Semiconductor Nanostructures
Autorzy:
Samarth, N.
Luo, H.
Furdyna, J. K.
Giebultowicz, T. M.
Awschalom, D. D.
Powiązania:
https://bibliotekanauki.pl/articles/1920966.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.25.+z
Opis:
We describe experiments which study static and dynamic aspects of Mn spin organization in magnetic semiconductor superlattices and quantum wells. Neutron diffraction studies of ZnSe/MnSe and ZnTe/MnSe superlattices show how static Mn spin organization in these antiferromagnetic layers may be modified by strain and lowered dimensionality. We also use a novel form of femtosecond magnetic spectroscopy to examine magnetic polaron dynamics in diluted magnetic semiconductor quantum wells, and show how the organization of Mn spins by a spin-polarized carrier population may be directly viewed in the time domain.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 573-584
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetic Exchange in Diluted Magnetic Semiconductors of Wurtzite Structure
Autorzy:
Blinowski, J.
Kacman, P.
Powiązania:
https://bibliotekanauki.pl/articles/1929720.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.-m
Opis:
Kinetic exchange between valence electrons and paramagnetic ions in diluted magnetic semiconductors of wurtzite structure is examined and compared with the results obtained previously for zinc-blende type diluted magnetic semiconductors. Two limiting electron configurations of the impurity ion, d$\text{}^{5}$ and d$\text{}^{1}$, are discussed. For the former, it is shown that the exchange constant anisotropy, experimentally observed in CdMnSe, results from the anisotropy of the hybridization matrix elements. In the latter case, apart from the similar anisotropy of the ferromagnetic exchange constant, additional, antiferromagnetic corrections should be expected, since for this particular symmetry the hybridization between the ground state of the ion and valence band becomes allowed.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 693-696
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Slow Relaxation of Resistance in Manganite Perovskite Nanoconstrictions
Autorzy:
Baszyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/1810570.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Lr
75.50.Pp
Opis:
The time decay of the surface resistance $R_{S}(t)$ was measured for the $La_{0.7}Sr_{0.3}MnO_{3}$ perovskite nanocontacts obtained by break technique at liquid nitrogen. The corresponding time relaxation can be described by two-term formula: stretched exponential function and logarithmic dependence. The characteristic times $τ_{1}$ and $τ_{2}$ of the relaxation processes are of order of seconds and few tens of seconds, respectively. The appearance of both contributions evidences the existence of two sources of relaxation, which can be assigned to inhomogeneous changes of the angle between the magnetic moments of the neighboring Mn ions inside spin blocks $(τ_{1})$ and between the spin blocks $(τ_{2})$ occurring near surface of the nano-electrodes. Similar to magnetic viscosity, the dependence of resistance viscosity $S_{R}$ on basis current is characterized by bell-shaped curve. These results point out the important role of the structural arrangements of the Mn-ions into spin blocks on the surfaces electrodes of the nanocontact.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 339-341
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Site Percolation Thresholds of FCC Lattice
Autorzy:
Gawron, T. R.
Cieplak, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1891423.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Mg
75.50.Pp
Opis:
Percolation thresholds, p$\text{}_{c}$, for site diluted spin systems on the fcc lattice are determined for exchange interactions extending up to the shell of the fourth nearest neighbors. If the interactions include the nearest, second, third, and fourth neighbors, p$\text{}_{c}$ is equal to 0.198, 0.136, 0.061, and 0.05 respectively. These results agree with the Roberts approximate formula for p$\text{}_{c}$. Estimation of p$\text{}_{c}$ to even longer-ranged couplings is presented. For instance for p$\text{}_{c}$ = 0.01 the range of the couplings should extend at least to the eight shell of neighbors.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 461-464
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of GaMnAs Single Layers and GaInMnAs Superlattices Investigated at Low Temperature and High Magnetic Field
Autorzy:
Hernandez, C.
Terki, F.
Charar, S.
Sadowski, J.
Maude, D.
Stanciu, V.
Svedlindh, P.
Powiązania:
https://bibliotekanauki.pl/articles/2036030.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.70.-i
Opis:
Magnetotransport properties of GaMnAs single layers and InGaMnAs/InGaAs superlattice structures were investigated at temperatures from 4 K to 300 K and magnetic fields up to 23 T to study the influence of carriers confinement through different structures. Both single layers and superlattice structures show paramagnetic-to-ferromagnetic phase transition. In GaMnAs/InGaAs superlattice beside the Curie temperature (T$\text{}_{c}$≈40 K), a new phase transition is observed close to 13 K.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 613-619
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR Spectra of Cr in CdTe Crystals
Autorzy:
Stefaniuk, I.
Bester, M.
Virt, I. S.
Kuzma, M.
Powiązania:
https://bibliotekanauki.pl/articles/2043654.pdf
Data publikacji:
2005-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Cr
Opis:
The EPR studies of CdTe:Cr were performed on X-band (9.6 GHz) spectrometer at room temperature. Single CdTe crystals were doped by chromium Cr in the synthesis process. The spectra observed were resolved into two spectra. The first one consisted of very broad line (Δ B=100 mT) and the second one showed a typical fine structure. The complete angular dependence measurements were obtained. The fine structure of Cr$\text{}^{2+}$ or Cr$\text{}^{3+}$ ions was assumed and simulated. It follows from the theoretical analysis of the obtained spectra that degree of ionization of the chromium Cr dopant is 3+.
Źródło:
Acta Physica Polonica A; 2005, 108, 2; 413-418
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in Eus-pbs Multilayers
Autorzy:
Story, T.
Swüste, C. H. W.
Swagten, H. J. M.
de Jonge, W. J. M.
Stachow-Wójcik, A.
Twardowski, A.
Arciszewska, M.
Dobrowolski, W.
Gałązka, R. R.
Sipatov, A. Yu.
Powiązania:
https://bibliotekanauki.pl/articles/2013042.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.70.Ak
Opis:
We present the results of ferromagnetic resonance studies of the thickness dependence of magnetic anisotropy in 2 series of EuS-PbS multilayers grown on (111) BaF$\text{}_{2}$ and (100) KCl substrates with the EuS thickness varying in the range d=6-70 Å. The anisotropy constant K was found to follow the dependence K(d)=K$\text{}_{V}$+2K$\text{}_{S}$/d , with the surface term K$\text{}_{S}$ larger for layers grown on BaF$\text{}_{2}$ as compared to KCl. This difference is discussed in terms of different thermal stress-induced distortions of cubic crystal lattice of EuS. We found that the thickness of EuS layer required for the perpendicular (to the layer) magnetization is d ≤ 2-3 Å, i.e., it is below 1 monolayer.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 435-438
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoelastic Anomalies and Suppression of Jahn-Teller Distortions in La$\text{}_{1-x}$Sr$\text{}_{x}$MnO$\text{}_{3}$ by Pulsed Magnetic Fields
Autorzy:
Kadomtseva, A. M.
Popov, Yu. F.
Vorob'ev, G. P.
Kamilov, K. I.
Ivanov, V. Yu.
Mukhin, A. A.
Balbashov, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2013240.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.50.Pp
Opis:
Thermal expansion Δl/l(T) and magnetostriction λ$\text{}_{∥, ⊥ }$(H,T) in the pulsed magnetic fields H up to 250 kOe were studied in the single La$\text{}_{1-x}$Sr$\text{}_{x}$MnO$\text{}_{3}$ crystals (x=0.1, 0 .125, and 0.15) at temperatures T=10-320 K. Anomalies in the Δl/l (T) curves were observed near a charge (polaron) ordering (T$\text{}_{p}$) and structural transitions between orthorhombic Jahn-Teller distorted O' phase and high temperature orthorhombic (pseudocubic) O$\text{}^{*}$ one (T'$\text{}_{s}$). A noticeable increase in the field-induced magnetostriction λ$\text{}_{∥, ⊥ }$(H) was revealed in the O' phase at T$\text{}_{p}$
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 599-602
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconductor Ferromagnetic Structures
Autorzy:
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2014124.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.70.Cn
Opis:
Ferromagnetic semiconductor structures such as superlattices or trilayers form a new class of magnetic systems composed entirely of semiconductor materials. The examples are Ga$\text{}_{1-x}$Mn$\text{}_{x}$As-AlGaAs with the ferromagnetic layer of GaMnAs semimagnetic (diluted magnetic) semiconductor or EuS-PbS with the ferromagnetic member (EuS) of the family of europium chalcogenides. We discuss the spectrum of perspective ferromagnetic semiconductor materials, the effect of size and stress on magnetic properties of ultrathin semiconductor ferromagnetic layers, and the effect of interlayer exchange in all-semiconductor systems.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 171-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetization of Pb$\text{}_{1-x}$Cr$\text{}_{x}$Te Semimagnetic Semiconductor
Autorzy:
Mac, W.
Story, T.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1876309.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.20.Hr
Opis:
We present experimental studies of magnetization of Pb$\text{}_{1-x}$Cr$\text{}_{x}$Te (x ≤ 0.01) crystals. The reasonable description of the data is obtained for a composition of x ≤ 0.001 using Cr$\text{}^{+++}$ model (Brillouin type paramagnetism S = 3/2).
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 492-494
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superexchange in A$\text{}^{II}$B$\text{}^{VI}$ Diluted Magnetic Semiconductors with Mn, Fe and Co Ions
Autorzy:
Blinowski, J.
Kacman, P.
Powiązania:
https://bibliotekanauki.pl/articles/1877065.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.-m
Opis:
A theory of superexchange, the dominant ion-ion spin interaction, for Mn-, Fe- and Co-based DMS is presented. The theory takes into account the band structure of A$\text{}^{II}$B$\text{}^{VI}$ compounds, the orbital dependence of the hybridization and the intra shell correlations of the d-electrons, which are essential in the case of the non-S-state ions. The general formulae relating the superexchange to the band structure and the ionic energy spectrum were obtained - the dominant part of the superexchange turns out to be inversely proportional to the square of the ionic spin. This explains the observed increase in the average values of d-d exchange constants, when passing from Mn via Fe to Co ions in DMS.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 539-542
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Magnetoelectric Effects within a Sandwich Structure with the Parabolic Quantum Well
Autorzy:
Gruhn, W.
Powiązania:
https://bibliotekanauki.pl/articles/1813600.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.50.Pp
Opis:
We study magnetic effects in a trilayer formed of magnetic layers separated by a spacer with a parabolic potential profile. The focus is on mechanisms of indirect magnetic interactions within the spacer. We show existence of magnetic oscillations and novel type of magnetoelectric effect.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 175-178
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemical Reduction of Chalcopyrite CuFeS₂: Changes in Composition and Magnetic Properties
Autorzy:
Baláž, P.
Zorkovská, A.
Baláž, M.
Kováč, J.
Tešinský, M.
Osserov, T.
Guseynova, G.
Ketegenov, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032642.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.05.Hd
Opis:
High-energy milling of sulphides with a reactive metal in so-called mechanochemical reduction mode can lead to products in nanorange and to composition which simplifies the following metallurgical processing. Chalcopyrite CuFeS₂, a ternary semiconductor with antiferromagnetic properties represents promising candidate as an advanced material for use in inexpensive nanoelectronics (solar cells, magnetic area), as well as copper ore source in metallurgical operations. In this work, the process of mechanochemical reduction of chalcopyrite with elemental iron is studied. The composition and properties of nanopowder prepared by high-energy milling were analyzed by X-ray diffraction and magnetic measurements. Most of the reaction takes place during 30 min with chalcocite Cu₂S and troilite FeS as the only reaction products. The magnetic investigations reveal significant increase of saturation magnetization as a result of milling. Unlike the conventional high-temperature reduction of chalcopyrite, the mechanochemical reduction is fast and ambient temperature and atmospheric pressure are sufficient for its propagation.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1165-1167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Paramagnetic Resonance of Cr in PbTe
Autorzy:
Story, T.
Wilamowski, Z.
Grodzicka, E.
Witkowska, B.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1929751.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
72.20.My
Opis:
We present the results of the low temperature electron paramagnetic resonance (EPR) and transport investigations of the crystals of Pb$\text{}_{1-x}$Cr$\text{}_{x}$Te (x ≤ 0.01). The samples with chromium concentrations x ≥ 0.0015 are all n-type. For these samples we observe the single EPR line with the g-factor decreasing from g = 1.97 till g = 1.93 with increasing carrier concentration. This resonance can be attributed to electrically and magnetically active Cr$\text{}^{3+}$ ions. The crystals with Cr concentration x ≤ 0.0015 may be both n- and p-type. The EPR spectrum of these samples consists of two lines: the one discussed above and the other one with g = 1.99 observed only for samples with electron concentration n ≤ 10$\text{}^{18}$ cm$\text{}^{-3}$.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 773-775
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Frequency Raman Spectrum οf Bulk $Zn_{0.984}Co_{0.016}O$ Crystal
Autorzy:
Szuszkiewicz, W.
Łusakowski, A.
Morhange, J.
Gołacki, Z.
Arciszewska, M.
Brodowska, B.
Kanehisa, M.
Klepka, M.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1807848.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
The influence of possible presence of $Co^{2+}$ ion pairs in a bulk $Zn_{1-x}Co_{x}O$ mixed crystal on the low-frequency part of the Raman spectrum is discussed. Two effects can be taken into account in the theoretical considerations when analyzing the energy level scheme corresponding to Co ions. The first is a local lattice deformation in the vicinity of $Co^{2+}$ ion due to a presence of the second ion, smaller than the host ZnO lattice cation. Such deformation creates a trigonal field, which can only slightly modify the energy levels of $Co^{2+}$ ion. The second effect, which results from an antiferromagnetic superexchange interaction between two $Co^{2+}$ ions is responsible for a new set of energy levels. The Raman data taken at low temperature on the sample corresponding to the composition x = 0.016 demonstrated the presence of two structures at about 6 $cm^{-1}$ and 13 $cm^{-1}$. These structures may be interpreted as electronic transitions between the ground state and the first excited state of a single $Co^{2+}$ ion in the substitution site of ZnO lattice and as a similar transition for $Co^{2+}$ ion pair, respectively.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 103-106
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering Dynamics of Free Excitons on Fe$\text{}^{++}$ Ions in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se
Autorzy:
Gaj, J. A.
Nguyen, The Khoi
Nawrocki, M.
Golnik, A.
Lebecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/1891231.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
Inelastic scattering of excitons on Fe$\text{}^{++}$ ions in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se was studied by resonant Raman scattering. Polarization measurements were done using a modulation technique, allowing for the first time to determine the full polarization state of the detected light. The obtained results were compared to a simple calculation in an incoherent model of scattering on Fe$\text{}^{++}$ ions.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 409-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering Dynamics of Excitons in ZnSe Based Semimagnetic Semiconductors
Autorzy:
Nguyen, The Khoi
Mac, W.
Gaj, J.A.
Powiązania:
https://bibliotekanauki.pl/articles/1921546.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
Resonant Raman scattering was measured for (Zn,Fe)Se and (Zn,Cr)Se with the magnetic ion mole fraction below 0.02. LO phonons and intra-Fe$\text{}^{++}$ transitions were observed. Polarization measurements versus magnetic field allowed to obtain polarization lifetimes (polariton flight times) in the sub-picosecond range.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 634-636
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Photomemory Effect in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$:In for Direct Measurements of Magnetization of Bound Magnetic Polarons
Autorzy:
Wojtowicz, T.
Koleśnik, S.
Miotkowski, I.
Furdyna, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/1921550.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.38.+i
75.50.Pp
Opis:
The first direct measurement of the magnetization of donor bound magnetic polarons in diluted magnetic semiconductors is reported. The experiment has been performed taking advantage of photomemory effect found in n-type Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ crystals doped with In. Good agreement between experimental results and theory of bound magnetic polarons is observed.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 637-640
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(Eu,Gd)Te - MBE Growth and Characterization
Autorzy:
Dziawa, P.
Taliashvili, B.
Domuchowski, W.
Łusakowska, E.
Arciszewska, M.
Demchenko, I.
Dobrowolski, W.
Dybko, K.
Fedorych, O. M.
Nadolny, A. J.
Osinniy, V.
Petrouchyk, A.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038228.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.15.Hi
Opis:
Monocrystalline thin layers of (Eu,Gd)Te, n-type ferromagnetic semiconductor, were grown by molecular beam epitaxy technique on BaF$\text{}_{2}$ (111) substrates. Reflection high-energy electron diffraction, X-ray diffraction, and atomic force microscopy characterization proved epitaxial mode of growth and high crystal quality of the layers. Magnetic susceptibility and magnetic resonance measurements showed that in (Eu,Gd)Te layers ferromagnetic transition takes place at about 13 K. Electrical characterization carried out by the Hall effect and resistivity measurements revealed very high electron concentration of 10$\text{}^{20}$~cm$\text{}^{-3}$ and sharp maximum of resistivity at transition temperature.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 215-221
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and Magnetic Properties of PbTe:Cr and PbSnTe:Cr
Autorzy:
Story, T.
Grodzicka, E.
Witkowska, B.
Górecka, J.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1924220.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
72.20.My
Opis:
We present the results of the experimental studies of the low temperature transport and magnetic properties of PbTe, Pb$\text{}_{1-x}$Sn$\text{}_{x}$Te (x ≤ 0.3) and SnTe crystals doped with 0.5 at.% of chromium. Cr was found to be a resonant donor in PbTe and PbSnTe. Magnetic susceptibility measurements revealed that PbTe:Cr and Pb$\text{}_{1-x}$Sn$\text{}_{x}$Te:Cr (x ≤ 0.2) are Curie paramagnets whereas SnTe:Cr exhibits van Vleck paramagnetism.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 879-881
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Exchange-Correlations Effects (+U Corrections) on the Energy Levels of Mn and Fe Impurities in GaN and AlN: A Comparison with Experiment
Autorzy:
Zakrzewski, T.
Bogusławski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399156.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.30.Fc
Opis:
Electronic structure of Mn and Fe impurities in GaN and AlN are calculated within the density functional theory in the generalized gradient approximation without and with the +U corrections. The comparison with the available experimental data shows that the results obtained with U = 0 are in good agreement with experiment. Inclusion of +U corrections makes the agreement worse.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 898-900
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Spectroscopy of Co-Doped ZnO Bulk Crystals
Autorzy:
Szuszkiewicz, W.
Morhange, J. F.
Gołacki, Z.
Łusakowski, A.
Schumm, M.
Geurts, J.
Powiązania:
https://bibliotekanauki.pl/articles/2047700.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
Low-temperature Raman spectra of a bulk mixed crystal Zn$\text{}_{1-x}$Co$\text{}_{x}$O (x = 0.016) are shown and analyzed. Besides the common modes of the ZnO host lattice, electronic transitions related to the presence of Co$\text{}^{2+}$ ions at the Zn sites are observed. In spite of the low Co concentration the presence of collective excitations corresponding to Co and CoO precipitates is also revealed.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 363-368
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Half-Parabolic Quantum Wells of Diluted Magnetic Semiconductor Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
Autorzy:
Kutrowski, M.
Wojtowicz, T.
Cywiński, G.
Karczewski, G.
Janik, E.
Dynowska, E.
Kossut, J.
Kossacki, P.
Fiederling, R.
Pfeuffer-Jeschke, A.
Ossau, W.
Powiązania:
https://bibliotekanauki.pl/articles/1968307.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.66.Hf
Opis:
We report on magnetooptical studies of MBE-grown half-parabolic CdTe/Cd$\text{}_{x}$Mn$\text{}_{1-x}$Te quantum well structures. The value of the valence band offset Q$\text{}_{v}$=0.4 ± 0.05 was determined by comparing energies of optical transitions in the absence of a magnetic field with model calculations. This value was verified by fitting the observed spin splitting of the lowest heavy hole (hh) state. We discuss also the temperature dependence of Q$\text{}_{v}$.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 887-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Photoemission Study of Sn$\text{}_{0.96}$Gd$\text{}_{0.04}$Te
Autorzy:
Orlowski, N.
Janowitz, C.
Müller, A.
Manzke, R.
Kowalski, B. J.
Orłowski, B. A.
Powiązania:
https://bibliotekanauki.pl/articles/1963395.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
79.60.-i
Opis:
Sn$\text{}_{0.96}$Gd$\text{}_{0.04}$Te has been studied by means of the resonant photoemission spectroscopy in the constant final states, constant initial states and energy distribution curves modes. In the constant final states spectrum of the well-known giant resonance at the 4d-4f threshold around 150 eV we were able to resolve a peak of the multiplet structure that has not previously been found. Spectra were also taken at the 4p-5d threshold around 280 eV revealing a double structure with antiresonating behaviour.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 847-850
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Ion Implantation on Magnetic Structural and Optical Properties of (Ga,Mn)As Epitaxial Films
Autorzy:
Yastrubchak, O.
Kulik, M.
Żuk, J.
Domagała, J.
Szymczak, R.
Wosiński, T.
Sadowski, J.
Tóth, A.
Powiązania:
https://bibliotekanauki.pl/articles/1812027.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
We performed implantation experiments, applying both the chemically active oxygen ions and inactive ions of neon noble gas, to thin epitaxial films of (Ga,Mn)As ferromagnetic semiconductor. Inspection of their magnetic properties by means of a superconducting quantum interference device magnetometer revealed that the implantation with a low dose of either O or Ne ions completely suppressed ferromagnetism in the films. Both the high resolution X-ray diffraction technique and the Raman spectroscopy showed significant changes in the structural and optical properties of the films caused by oxygen implantation and confirmed the preservation of high structural and optical quality of the neon implanted (Ga,Mn)As films.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1445-1450
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
XANES Studies of Mn K and $L_{3,2}$ Edges in the (Ga,Mn)As Layers Modified, by High Temperature Annealing
Autorzy:
Wolska, A.
Lawniczak-Jablonska, K.
Klepka, M.
Jakieła, R.
Demchenko, I.
Sadowski, J.
Holub-Krappe, E.
Persson, A.
Arvanitis, D.
Powiązania:
https://bibliotekanauki.pl/articles/1812244.pdf
Data publikacji:
2008-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
75.50.Pp
Opis:
$Ga_{1-x}Mn_xAs$ is commonly considered as a promising material for microelectronic applications utilizing the electron spin. One of the ways that allow increasing the Curie temperature above room temperature is to produce second phase inclusions. In this paper $Ga_{1-x}Mn_xAs$ samples containing precipitations of ferromagnetic MnAs are under consideration. We focus on the atomic and electronic structure around the Mn atoms relating to the cluster formation. The changes in the electronic structure of the Mn, Ga and As atoms in the (Ga,Mn)As layers after high temperature annealing were determined by X-ray absorption near edge spectroscopy. The experimental spectra were compared with the predictions of ab initio full multiple scattering theory using the FEFF 8.4 code. The nominal concentration of the Mn atoms in the investigated samples was 6% and 8%. We do not observe changes in the electronic structure of Ga and As introduced by the presence of the Mn atoms. We find, in contrast, considerable changes in the electronic structure around the Mn atoms. Moreover, for the first time it was possible to indicate the preferred interstitial positions of the Mn atoms.
Źródło:
Acta Physica Polonica A; 2008, 114, 2; 357-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Phase Diagram of the Second-Type Antiferromagnet
Autorzy:
Balcerzak, T.
Radomska, A.
Powiązania:
https://bibliotekanauki.pl/articles/2013394.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.-b
75.50.Ee
75.50.Pp
Opis:
We investigate theoretically the phase diagrams of the second-type antiferromagnet with the fcc structure. Besides the nearest-neighbour and next-nearest-neighbour exchange interactions, the biquadratic and long-range dipolar terms are taken into account. The results can be useful to discuss the phase diagram of europium telluride under external pressure.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 775-778
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculations of EuTe Magnetic Phase Diagram for External Pressure
Autorzy:
Radomska, A.
Balcerzak, T.
Powiązania:
https://bibliotekanauki.pl/articles/2014065.pdf
Data publikacji:
2000-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.-b
75.50.Pp
75.50.Ee
Opis:
The magnetic phase diagram of europium telluride, EuTe, under external high pressure is theoretically investigated. Besides nearest-neighbour and next-nearest-neighbour exchange interactions, the long-range dipolar and biquadratic interactions are taken into account. The functional dependences of these interactions on the lattice constant are proposed. The calculated Néel and Curie temperatures are compared with the experimental data. Two new phases, antiferrimagnetic and ferrimagnetic, have been found at a high pressure and low temperatures.
Źródło:
Acta Physica Polonica A; 2000, 98, 1-2; 83-91
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Symmetry-Induced Hybridization in Hexagonal and Zinc-Blende CrTe Crystals
Autorzy:
Kuzma, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402568.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Ah
75.50.Cc
75.50.Pp
Opis:
Transition metal chalcogenides of a zinc-blende structure are theoretically predicted to be half metallic and, therefore, they are interesting for spintronic applications. However, the ground state of these compounds is hexagonal, of NiAs type, whereas the cubic phase is a metastable one. Here, we investigate the Cr-Te bondings of both phases of Cr-Te from point of view of symmetry. The hybridization in octahedral and tetrahedral lattice is studied for both structures. The fiber bundle presentation of the hybridization problem is also addressed.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 185-189
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oscillating Antiferromagnetism of Ultrathin EuTe Layers
Autorzy:
Wilamowski, Z.
Springholz, G.
Svrcek, V.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1968444.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Ee
76.50.+g
Opis:
We study magnetic resonance on EuTe/PbTe superlattices. Analysis of the magnetic dipole anisotropy in the superlattices and of the EPR amplitude of isolated Eu ions in the PbTe wells shows that the diffusion at interfaces is very small. The real thickness of EuTe can be evaluated with an accuracy better than one monolayer. Since for EuTe layers thicker than 2 monolayers there is no difference in the character of the antiferromagnetic resonance observed for even and odd numbers of monolayers, we conclude that there is no static magnetization of the antiferromagnetic sublattices. Nevertheless, long range antiferromagnetic order is clearly evident.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1051-1054
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Semiconductor-Antiferromagnet Superlattices
Autorzy:
Wilamowski, Z.
Buczko, R.
Jantsch, W.
Ludwig, M.
Springholz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1952426.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.50.Pp
76.50.+g
Opis:
Magnetic resonance investigations of ultra-thin antiferromagnetic EuTe layers show a specific behaviour in the quasi-2D antiferromagnetic ordering: (i) an anisotropy of the critical broadening, (ii) a substantial increase in the Néel temperature and (iii) an anisotropic shift of the resonance frequency which diverges at the Néel point. The results show that exchange coupling is stronger in quasi-2D than in 3D antiferromagnetic samples and that correlation of spin chains aligned in the perpendicular direction occurs already well above the Néel point.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 973-976
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific Heat and Magnetic Properties of Single-Crystalline $(Zn_{0.925}In_{0.054})[Cr_{1.84}In_{0.152}]Se_4$ Semiconductor
Autorzy:
Malicka, E.
Groń, T.
Pacyna, A.
Ślebarski, A.
Goraus, J.
Gągor, A.
Mydlarz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1409656.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.Ba
75.50.Ee
75.50.Pp
Opis:
An antiferromagnetic order with a Néel temperature $T_{N}$ = 17.5 K, a strong ferromagnetic exchange evidenced by a positive Curie-Weiss temperature $\Theta_{CW}$ = 77.3 K, the fuzzy peaks in the real component of susceptibility χ'(T) and the disappearance of the second critical field were established. The curvature of specific heat C(T) and C(T)/T in surrounding of $T_{N}$ indicated a broad peak, characteristic for the system with inhomogeneous magnetic state (spin-glass-like phase). The calculated magnetic entropy showed the value of S(T) ≈ 1 J/(mol K) which is extremely small; i.e., much lower than the magnetic contribution Rln(2S + 1) = 11.52 J/(mol K) calculated for the spin 3/2.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1108-1110
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hopkinson-Like Effect in Single-Crystalline $CdCr_2Se_4$ and $Cd[Cr_{1.89}Ti_{0.08}]Se_4$
Autorzy:
Malicka, E.
Groń, T.
Pacyna, A.
Duda, H.
Krok-Kowalski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1489913.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Jc
75.50.Pp
75.50.Dd
Opis:
The static (dc) and dynamic (ac) magnetic measurements of $CdCr_2Se_4$ and $Cd[Cr_{1.89}Ti_{0.08}]Se_4$ showed their ferromagnetic properties with a Curie temperature $T_{C}$ ≈ 130 K and revealed on the real component of ac susceptibility curve, the peaks near $T_{C}$ at 200 Oe, 450 Oe and 1 kOe, characteristic for the Hopkinson ones. The meaningful reduction of saturation moment to 4.73 $μ_{B}$/f.u. for $Cd[Cr_{1.89}Ti_{0.08}]Se_4$ suggests the diamagnetic configuration of Ti ions, which dilutes the ferromagnetic sublattice of Cr ones and causes reducing of the energy losses visible on the imaginary components of ac susceptibility curve. Close for zero values of higher susceptibility harmonics above $T_{C}$ are pointing out to the lack of the spin fluctuations in the paramagnetic state.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 690-693
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical and Magnetic Characterization οf $ZnCr_{2-x}V_{x}Se_{4}$ Spinel Semiconductors
Autorzy:
Duda, H.
Malicka, E.
Groń, T.
Pacyna, A.
Kusz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791367.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Jc
75.50.Pp
75.50.Dd
Opis:
Single crystals of $ZnCr_{2}Se_{4}$ spinel doped with vanadium were prepared by chemical vapour transport. The chemical compositions of three crystals have been determined by X-ray diffraction. The structure refinement using the SHELXL-93 program system determine the cation distribution in the system as $ZnCr_{2-x}V_{x}Se_{4}$. For x values equal to 0.03, 0.1 and 0.13 the observed symmetry was cubic, space group Fd3m. Based on the structural data, influence of the V ions on the magnetic and electrical properties has been analyzed.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 962-963
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical and Magnetic Studies of the $Cd_{x}Cr_{y}V_{z}Se_{4}$ Spinels
Autorzy:
Groń, T.
Duda, H.
Malicka, E.
Zawisza, B.
Krok-Kowalski, J.
Pacyna, A.
Powiązania:
https://bibliotekanauki.pl/articles/1791407.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Jc
75.50.Pp
75.50.Dd
Opis:
The electrical and magnetic investigations carried out on the polycrystalline spinels with the general chemical formula $Cd_{x}Cr_{y}V_{z}Se_{4}$ (where z = 0.06, 0.12, 0.24, and 0.31) revealed semiconducting and ferromagnetic properties with a Curie temperature of 127.5 K. A step-like structure of the electrical conductivity, σ(T), was observed for the polycrystal containing 6% V ions in the octahedral sites while the remaining samples showed a typical Arrhenius behaviour of σ(T). These effects are interpreted in terms of ferromagnetic spin clusters which finally dissolve on going towards the paramagnetic limit including non-stoichiometry.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 969-970
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in (Ge,Mn)Te Layers
Autorzy:
Knoff, W.
Łusakowski, A.
Wołoś, A.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/1386196.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
76.50.+g
Opis:
Ferromagnetic resonance study of magnetic anisotropy is presented for thin layers of IV-VI diluted magnetic semiconductor (Ge,Mn)Te with Mn content of 12 and 21 at.% grown by molecular beam epitaxy on BaF₂ (111) substrates. The layers with low Mn content grow in the rhombohedral crystal structure and exhibit perpendicular magnetic anisotropy whereas the layers with Mn content higher than about 20 at.% are of cubic (rock-salt) structure and show regular easy-plane type magnetic anisotropy. The quantitative analysis of the angular dependence of the ferromagnetic resonant field is performed taking into account the magnetic energy contributions due to rhombohedral distortion (axial term along the (111) growth direction of the layer) and the crystal field terms allowed for ferromagnetic systems of rhombohedral symmetry.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 404-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetic Order in Single-Crystalline (Cd$\text{}_{x}$Al$\text{}_{y}$)[Cr$\text{}_{2}$]Se$\text{}_{z}$ Semiconductors
Autorzy:
Duda, H.
Rduch, P.
Malicka, E.
Groń, T.
Kusz, J.
Powiązania:
https://bibliotekanauki.pl/articles/2048125.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Jc
75.50.Pp
75.50.Dd
Opis:
Measurements of the magnetic properties, the electrical conductivity and the Seebeck effect were performed on single crystals (Cd$\text{}_{x}$Al$\text{}_{y}$)[Cr$\text{}_{2}$]Se$\text{}_{z}$ between 77 and 300 K. All samples have a ferromagnetic order with the Curie temperature of 130 K and the paramagnetic Curie-Weiss temperature of 155 K. Both these temperatures do not depend significantly on the Al substitution. The electrical conductivity of single crystals CdCr$\text{}_{2}$Se$\text{}_{4}$ doped with Al was p-type and showed the change of log σ versus 1/T slope above 150 K. This fact is interpreted as being due to the onset of impurity conduction and structural defects.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 702-704
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetism in Cr-Based Diluted Magnetic Semiconductors
Autorzy:
Blinowski, J.
Kacman, P.
Majewski, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/1933725.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Gm
75.50.Pp
75.50.Dd
Opis:
It has been recently established that in zinc chalcogenides with Cr$\text{}^{2+}$ paramagnetic ions the p-d interactions are ferromagnetic. We clarify the origins of this property and make predictions concerning other Cr-based diluted magnetic semiconductors. The observation of the ferromagnetic p-d interaction resuscitated hopes for ferromagnetic d-d exchange interactions in diluted magnetic semiconductors. We have calculated the nearest-neighbor superexchange integrals in Cr-based diluted magnetic semiconductors. No simple correlation between the signs of p-d and d-d interactions has been found. Still, there are extended energy regions where the calculated superexchange is ferromagnetic and the act ual parameters of DMS with Cr$\text{}^{2+}$ seem to match these regions.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 683-686
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and Magnetic Properties of Low Temperature Annealed Ga$\text{}_{1-x}$Mn$\text{}_{x}$As
Autorzy:
Kuryliszyn, I.
Wojtowicz, T.
Liu, X.
Furdyna, J. K.
Dobrowolski, W.
Broto, J.-M.
Goiran, M.
Portugall, O.
Rakoto, H.
Raquet, B.
Powiązania:
https://bibliotekanauki.pl/articles/2035604.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Dd
81.40.Rs
Opis:
We present the results of low temperature annealing studies of Ga$\text{}_{1-x}$Mn$\text{}_{x}$As epilayers grown by low temperature molecular beam epitaxy in a wide range of Mn concentrations (0.01
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 659-665
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and structural studies of GeMnSnTe epitaxial layers
Autorzy:
Grochot, A.
Knoff, W.
Taliashvili, B.
Wołkanowicz, W.
Minikayev, R.
Pieniążek, A.
Łusakowska, E.
Sawicki, M.
Jantsch, W.
Story, T.
Przybylińska, H.
Powiązania:
https://bibliotekanauki.pl/articles/1055147.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Pp
76.50.+g
Opis:
MBE grown Ge_{1-x-y}Mn_xSn_yTe layers with Mn content ranging from 10 to 30% and Sn content ranging from 2 to 5% have been characterized with X-ray diffraction, energy-dispersive X-Ray spectroscopy, atomic force microscopy, SQUID magnetometry, and ferromagnetic resonance. All layers (except the one with the highest Mn and Sn content) were found to be single phase rhombohedral, with the distortion axis perpendicular to the layer surface, and ferromagnetic. Ferromagnetic resonance studies have shown that co-doping with a few percent of tin makes the lattice more rigid and changes considerably the magnetocrystalline anisotropy, from purely uniaxial in GeMnTe to distorted cubic in Ge_{1-x-y}Mn_xSn_yTe at the same Mn content.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 340-342
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconducting Properties of $Cu_5SbO_6$
Autorzy:
Groń, T.
Filipek, E.
Dąbrowska, G.
Duda, H.
Mazur, S.
Kukuła, Z.
Pawlus, S.
Powiązania:
https://bibliotekanauki.pl/articles/1409627.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
72.20.Pa
75.50.Gg
Opis:
Thermoelectric power, electrical resistivity, I-V characteristics, relative electrical permittivity, dc magnetization and ac magnetic susceptibility measurements carried out on $Cu_5SbO_6$ showed p-type semiconducting behaviour with the activation energy of 0.24 eV as well as ferrimagnetic order with the Néel temperature of 5.2 K. The effective magnetic moment of 5.857 $μ_{B}$/f.u. revealed the orbital contribution to the magnetic moment. Large value of the relative electrical permittivity indicated that the $Cu^{2+}$ ions with the unscreened and unfilled electron shells are responsible for the polarizability and forming of electric dipoles.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1105-1107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mictomagnetic Order in Cd$\text{}_{0.87}$Cr$\text{}_{1.93}$V$\text{}_{0.06}$Se$\text{}_{4}$ Semiconductor
Autorzy:
Groń, T.
Malicka, E.
Zawisza, B.
Duda, H.
Krok-Kowalski, J.
Pacyna, A. W.
Powiązania:
https://bibliotekanauki.pl/articles/2048136.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Jc
75.50.Pp
75.50.Dd
Opis:
The complex ac dynamic magnetic susceptibility was used to study the mictomagnetic-like behavior in polycrystalline Cd$\text{}_{0.87}$Cr$\text{}_{1.93}$V$\text{}_{0.06}$Se$\text{}_{4}$ spinel. The temperature dependences of the zero field in-phase (real part) and out-of-phase (imaginary part) components of fundamental susceptibility measured at the oscillating field H$\text{}_{ac}$ = 0.5 Oe and at the constant frequency of 125 Hz are characteristic for the mictomagnetic order. These results well correlate with the anomalies in the second and third harmonics of the ac susceptibility indicating the cluster glass.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 714-716
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in Pb$\text{}_{1-x-y}$Sn$\text{}_{y}$Mn$\text{}_{x}$Te Studied by Ferromagnetic Resonance
Autorzy:
Eggenkamp, P. J. T.
Story, T.
Swüste, C. H. W.
Swagten, H. J. M.
de Jonge, W. J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1861517.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.50.+g
75.30.Gw
75.50.Pp
Opis:
We will report on the anisotropy in (Pb)SnMnTe, studied by ferromagnetic resonance. We have found a cubic anisotropy with a = 73 × 10$\text{}^{-4}$ cm$\text{}^{-1}$ for Sn$\text{}_{1-x}$Mn$\text{}_{x}$Te and a = 200 × 10$\text{}^{-4}$ cm$\text{}^{-1}$ for Pb$\text{}_{0.28-x}$Sn$\text{}_{0.72}$Mn$\text{}_{x}$Te. We will indicate some possible explanations for this anomalously large anisotropy.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 641-644
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Short Period InGaMnAs/InGaAs Superlattices
Autorzy:
Sadowski, J.
Mathieu, R.
Svedlindh, P.
Kanski, J.
Karlsteen, M.
Świątek, K.
Domagała, J. Z.
Powiązania:
https://bibliotekanauki.pl/articles/2035614.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.+a
75.50.Pp
75.25.+z
Opis:
We have observed a paramagnetic-to-ferromagnetic phase transition in short period InGaMnAs/InGaAs superlattices. The thicknesses of magnetic InGaMnAs layers in the structures studied was chosen to be 4 or 8 molecular layers (12Å or 24Å). The non-magnetic InGaAs spacer layers are 12Å thick. The composition (In content) in InGaMnAs and InGaAs was chosen in such a way that magnetic layers were: deep potential wells, high potential barriers, or shallow potential wells. For superlattices with 8 monolayer thick InGaMnAs magnetic layers and 4 monolayer thick InGaAs non-magnetic spacers the temperatures of paramagnetic-to-ferromagnetic phase transition do not depend on the band offsets between InGaMnAs and InGaAs adjusted by the In content.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 687-694
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Interlayer Magnetic Coupling in All-Semiconductor Superlattices by Means of Neutron Scattering Techniques
Autorzy:
Kępa, H.
Giebultowicz, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/2030768.pdf
Data publikacji:
2002-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.25.+z
75.50.Pp
75.75.+a
Opis:
An overview of neutron scattering studies of ferromagnetic and antiferromagnetic all-semiconductor superlattices is presented. Diffraction experiments on MnTe/CdTe, MnTe/ZnTe and EuTe/PbTe superlattices show pronounced correlations between the MnTe and EuTe layers across the non-magnetic spacers, even though these layers are antiferromagnetic and the systems are nearly-insulating. Current theory status of these systems is discussed. Diffractometry and reflectometry data from EuS/PbS superlattices reveal pronounced antiferromagnetic coupling between the ferromagnetic EuS block. First polarized neutron reflectometry data from superlattices prepared of a novel ferromagnetic"spintronics" material, Ga(Mn)As, are also presented.
Źródło:
Acta Physica Polonica A; 2002, 102, 1; 21-34
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strain Designed Magnetic Properties of III-V Magnetic Semiconductors
Autorzy:
Stagraczyński, S.
Jasiukiewicz, C.
Dugaev, V.
Berakdar, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402582.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
75.80.+q
Opis:
We present the theoretical analysis of a possibility of the magnetic anisotropy control using various components of the strain tensor in III-V magnetic semiconductor. We used the Kane model of the valence bands for the numerical simulations of the influence of strain on the Mn doped GaAs valence band structure. Calculating numerically the energy structure of deformed GaMnAs magnetic semiconductor, we also found the total energy of electron system as a function of orientation of the average magnetization vector. Our calculations show how the direction of the magnetization easy axis can be effectively rotated by using different types of deformation.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 219-221
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Cu, Ga and Au Dopants and Technology Conditions on the Magnetic Interactions in $HgCr_2Se_4$ Single Crystals
Autorzy:
Krok-Kowalski, J.
Władarz, G.
Groń, T.
Duda, H.
Pacyna, A.
Nikiforov, K.
Rduch, P.
Powiązania:
https://bibliotekanauki.pl/articles/1493008.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Kz
75.30.Et
Opis:
For single crystals $HgCr_2Se_4$ doped by nonmagnetic $Cu^{+},$ $Au^{2+}$ and $Ga^{3+}$ ions and single crystals of $HgCr_2Se_4$ matrix growing in different synthesis conditions both the dc and ac magnetic susceptibility as well as the magnetization have been measured. As it follows from the analysis of the obtained results, paradoxically, the dopants strengthen the long range magnetic interactions of the ferromagnetically ordered single crystals under study, evidenced by the higher values of the ordering temperature in comparison with those ones for pure matrix. An influence of the technological processes connected with deficiency and/or excess of Hg on the long range magnetic interactions was not observed.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 970-972
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Temperature on Critical Fields in $Zn_{x}Sb_{y}Cr_{z}Se_{4}$
Autorzy:
Malicka, E.
Groń, T.
Duda, H.
Pacyna, A.
Krok-Kowalski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791371.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Kz
75.30.Et
Opis:
The electrical and complex ac dynamic magnetic susceptibility measurements were used to study an influence of temperature on critical fields in single-crystalline $Zn_{x}Sb_{y}Cr_{z}Se_{4}$ spinel system with y = 0.11, 0.16 and 0.20. The p-type conduction and a shift both of the Néel temperature $T_{N}$ to lower temperatures and a susceptibility peak at $T_{m}$ in the paramagnetic region - to higher temperatures were established. Below $T_{N}$ the magnetic field dependence of susceptibility, $χ_{ac}(H)$, shows two peaks. First peak at the critical field $H_{c1}$ slightly decreases with temperature and remains almost constant as Sb content increases. Second peak at the critical field $H_{c2}$ drops rapidly with temperature and remains almost unchanged as Sb content increases. At $T_{N}$ both critical fields disappear.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 964-966
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Substitution of the Chromium Ions by the Nonmagnetic Sb and Al Ions on the Magnetization Processes in $CuCr_{2}X_{4}$ ( rm X = S, Se) Spinels
Autorzy:
Malicka, E.
Krok-Kowalski, J.
Warczewski, J.
Groń, T.
Duda, H.
Mydlarz, T.
Pawełczyk, M.
Pacyna, A.
Rduch, P.
Władarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1791401.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Kz
75.30.Et
Opis:
Both the dc and ac magnetic susceptibilities as well as magnetization measurements were used to study the influence of the dilution of the magnetic chromium subarray by nonmagnetic antimony and aluminium ions on the magnetization processes for four spinel families under investigation. Substitution of the chromium ions by the nonmagnetic Sb and Al ions in the compounds under study leads to the very hard magnetization in the case of the compounds with Sb and very easy magnetization in the compounds with Al. This effect is connected with the electronic configurations of the Sb and Al ions as well as with ionic radii of these cations.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 967-968
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diluted Magnetic Semiconductors in High Magnetic Fields
Autorzy:
Shapira, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1931897.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Fr
75.50.Pp
75.30.Et
Opis:
Magnetization studies of diluted magnetic semiconductors in high fields are reviewed. Magnetization steps due to pairs were originally used to measure the near neighbor exchange constant J$\text{}_{1}$. They are now also used to determine: (1) the smaller exchange constants J$\text{}_{2}$ and J$\text{}_{3}$, (2) the difference between J$\text{}_{1}$'s for inequivalent near neighbors in wurtzite diluted magnetic semiconductors, and (3) the Dzyaloshinski-Moriya interaction. A different type of magnetization step, due to isolated ions, is used to determine the uniaxial anisotropy of Co$\text{}^{++}$ ions in wurtzite diluted magnetic semiconductors. In Fe-based diluted magnetic semiconductors the high-field magnetization exhibits two effects: (1) strong dependence on field direction in cubic diluted magnetic semiconductors, and (2) reversal of the uniaxial magnetization-anisotropy in wurtzite diluted magnetic semiconductors. In (100) EuTe/PbTe superlattices the antiferromagnetic transition, both at zero and finite H, is depressed when the EuTe layer becomes only a few monolayers thick. The easy directions are in the (100) plane of the layer, which is explained by the dipole-dipole anisotropy.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 107-117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of (Ga,Mn)As
Autorzy:
Sawicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/2038212.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
75.70.-i
Opis:
A review is given of experimental findings and theoretical understanding of micromagnetic properties of zinc-blende ferromagnetic semiconductors, with (Ga,Mn)As taken as a sole example. It is emphasised that the Zener p-d model explains quantitatively the effect of strain on the easy axis direction as well as it predicts correctly the presence of the reorientation transition, observed as a function of hole concentration and temperature. Possible suggestions put forward to explain the existence of in-plane uniaxial magnetocrystalline anisotropy are then quoted.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 119-130
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interaction Between Magnetic Layers in Structures with Narrow-Gap IV-VI Semiconductors
Autorzy:
Dugaev, V. K.
Litvinov, V. I.
Dobrowolski, W.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2013062.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Cn
75.50.Pp
75.70.Ak
Opis:
The results of calculation of the indirect exchange interaction between magnetic layers are presented for the case of a structure with narrow-gap semiconducting IV-VI quantum well. The main mechanism is a magnetic polarization of the size-quantized electrons and holes inside the well. This type of interaction is suggested for the explanation of recent experiments on EuS/PbS structures.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 455-458
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Monte Carlo Study of Critical Properties of Strongly Diluted Magnetic Semiconductor (Ga,Mn)As
Autorzy:
Tomczak, P.
Diep, H.
Jabłoński, P.
Puszkarski, H.
Powiązania:
https://bibliotekanauki.pl/articles/1030426.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.10.Nr
75.30.Hx
Opis:
Within a Monte Carlo technique we examine critical properties of diluted bulk magnetic semiconductor (Ga,Mn)As modeled by a strongly diluted ferromagnetic Heisenberg spin-5/2 system on a face centered cubic lattice. We assumed that 5% of Ga atoms is substituted by Mn atoms and the interaction between them is of the RKKY-type. The considered system is randomly quenched and a double average was performed: firstly, over the Boltzmann probability distribution and secondly - over 2048 configurations related to the quenched disorder. We estimated the critical temperature: T_{c}=97±6 K, which is in agreement with the experiment.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 514-516
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Paramagnetism of Cu_3RE_2W_4O_{18} Semiconductors (RE = Gd, Dy-Er)
Autorzy:
Groń, T.
Tomaszewicz, E.
Duda, H.
Mazur, S.
Powiązania:
https://bibliotekanauki.pl/articles/1399149.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.20.-g
75.30.Cr
Opis:
$Cu_3RE_2W_4O_{18}$ tungstates (RE = Gd, Dy-Er) are paramagnets in the temperature range 4.2-300 K visible also in the absence of the energy losses in the curve of the imaginary part of magnetic susceptibility, χ". The negative values of the paramagnetic Curie-Weiss temperature, θ, may suggest the weak antiferromagnetic coupling below 4.2 K. The temperature independent component of magnetic susceptibility has a positive value indicating a domination of the Van Vleck contribution. Calculations of the effective number of the Bohr magnetons revealed that the orbital contribution to the magnetic moment comes mainly from the $RE^{3+}$ ions.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 885-887
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Coupling in CuCr$\text{}_{2}$X$\text{}_{4}$ (X = S, Se) Spinel Compounds Obtained via Substitution of the Chromium Ions by Nonmagnetic Sb or Al Ions
Autorzy:
Krok-Kowalski, J.
Malicka, E.
Władarz, G.
Groń, T.
Pawełczyk, M.
Heimann, J.
Pacyna, A. W.
Powiązania:
https://bibliotekanauki.pl/articles/2048127.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Kz
75.30.Et
Opis:
Taking into account both the dc magnetic susceptibility and the magnetization measurements as well as the high-temperature expansion of the magnetic susceptibility procedure the hopping integrals and superexchange integrals for the first and second coordination sphere were evaluated. The two hopping integrals are positive and many times greater than the superexchange ones. The obtained results testify to that in the stoichiometric compounds under study the double-exchange magnetic interaction is the main mechanism responsible for very strong, ferromagnetic coupling. Using the total hopping integral B the bandwidth of mixed valence band of chromium ions was determined.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 705-707
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Properties and Dynamic Susceptibility of MnTe Systems
Autorzy:
Wilczyński, M.
Świrkowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/1968441.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.10.Lp
75.70.-i
Opis:
Thin MnTe films are investigated. Electronic structure, local density of states and local magnetic moments are calculated for systems with ferromagnetic and antiferromagnetic order. Spin-dependent modifications of the density of states near the surface are results of the changes in p-d hybridization. Magnetic longitudinal and dielectric susceptibilities are calculated.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1048-1050
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Itinerant Theory of Exchange Constants in Diluted Co-Based Semimagnetic Semiconductors
Autorzy:
Mašek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1888118.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Lp
75.30.Ef
75.50.Pp
Opis:
The exchange constants in diluted semimagnetic semiconductors with Co are much larger than in the Mn doped systems. To explain this, we use a semiquantitative, tight binding version of the coherent potential approach and calculate the electronic structure of II-VI mixed semiconductors containing Co and Mn. The exchange constants are deduced from energies of spin reversal processes. The presence of the Co 3d states at the top of the valence band leads to the observed enhancement of the exchange coupling.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 267-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical and Magnetic Studies of $Zn_{x}Mn_{y}Cr_{z}Se_{4}$ p-Type Semiconductors
Autorzy:
Jendrzejewska, I.
Groń, T.
Duda, H.
Zajdel, P.
Pacyna, A.
Maciążek, E.
Powiązania:
https://bibliotekanauki.pl/articles/1791347.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Kz
75.30.Et
Opis:
The structural, electrical and magnetic investigations carried out on the $Zn_{x}Mn_{y}Cr_{z}Se_{4}$ polycrystals with y = 0.19, 0.29 and 0.38 revealed the spinel structure with the Mn ions occupying tetrahedral sites, p-type conduction with polaronic transport at high temperatures and antiferromagnetic order with a Néel temperature of 20 K and a Curie-Weiss temperature of 103 K. With increasing Mn content in a sample both the effective magnetic moment and the re-entrant temperature increase while the first and second critical fields connected with a metamagnetic transition and the breakdown of the conical spin arrangement decrease, respectively. These results are interpreted in terms of giant cubic anisotropy as well as an effect of Mn impurities on the screw structure of $ZnCr_{2}Se_{4}$.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 913-915
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Cation Substitution on Critical Fields in the n-type $Zn_{x}Sn_{y}Cr_{z}Se_{4}$ Spinel Semiconductors
Autorzy:
Groń, T.
Jendrzejewska, I.
Maciążek, E.
Pacyna, A.
Duda, H.
Zajdel, P.
Krok-Kowalski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791416.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Kz
75.30.Et
Opis:
The ac dynamic magnetic susceptibility was used to study a cation substitution on critical fields in polycrystalline ($Zn_{0.87}Sn_{0.048})Cr_{2.02}Se_{4}$ and $Zn_{0.93}[Cr_{1.95}Sn_{0.05}]Se_{4}$ spinels with tetra- and octahedral coordination of Sn ions, respectively. An increasing static magnetic field shifts the Néel temperature $T_{N}$ to lower temperatures while a susceptibility peak at $T_{m}$ in the paramagnetic region - to higher temperatures. Below $T_{N}$ the magnetic field dependence of susceptibility, $χ_{ac}(H)$, shows two peaks at critical fields $H_{c1}$ and $H_{c2}$. The values of $H_{c1}$ decrease slightly with temperature while the values of $H_{c2}$ decrease strongly with temperature, especially for spinel with octahedral coordination of Sn ions, suggesting a weakness of the ferromagnetic component.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 971-974
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetic Transition in $Ge_{1-x}Mn_{x}Te$ Layers
Autorzy:
Knoff, W.
Domukhovski, V.
Dybko, K.
Dziawa, P.
Jakieła, R.
Łusakowska, E.
Reszka, A.
Świątek, K.
Taliashvili, B.
Story, T.
Szałowski, K.
Balcerzak, T.
Powiązania:
https://bibliotekanauki.pl/articles/1791343.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Et
81.15.Hi
Opis:
Ferromagnetic transition temperature in thin layers of diluted magnetic (semimagnetic) semiconductor $Ge_{1-x}Mn_{x}Te$ was studied experimentally by SQUID magnetometry method and analyzed theoretically for a model Ising-type diluted magnetic system with Ruderman-Kittel-Kasuya-Yosida indirect exchange interaction. The key features of the experimentally observed dependence of the Curie temperature on Mn content (x ≤ 0.12) and conducting hole concentration p = (1-10) × $10^{21} cm^{-3}$ were reproduced theoretically for realistic valence band and crystal lattice parameters of p-$Ge_{1-x}Mn_{x}Te$ taking into account short carrier mean free path encountered in this material and Ruderman-Kittel-Kasuya-Yosida mechanism with both delta-like and diffused character of spatial dependence of the exchange coupling between magnetic ions and free carriers.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 904-906
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of (Zn,Mn)Te Semimagnetic Alloy Co-Doped with Chromium
Autorzy:
Avdonin, A.
Van Khoi, Le
Knoff, W.
Gałązka, R.
Powiązania:
https://bibliotekanauki.pl/articles/1791420.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
75.50.Pp
75.60.Ej
Opis:
Results of simultaneous doping of ZnTe with manganese and chromium are presented. An increase of magnetization of ferromagnetic Cr-related clusters with manganese concentration is observed. Phosphorus doping prevents the formation of ferromagnetic clusters.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 974-975
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Dependent Interaction of a Band Electron with Paramagnetic Impurities
Autorzy:
Blinowski, J.
Kacman, P.
Powiązania:
https://bibliotekanauki.pl/articles/1879507.pdf
Data publikacji:
1991-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.-m
71.70.-d
Opis:
A band electron interacting with N electrons in a d-shell of a paramagnetic impurity in zinc-blende type semiconductors was considered. The hybridization of band and d-states in the crystal field and the nonorthogonality mechanisms of interaction were examined in addition to the standard direct exchange. The Heisenberg-type form was derived for the interaction between a Γ$\text{}_{8}$-electron and an impurity with a half-filled d-shell. The domination of the hybridization mechanism explains the observed sign of the effective exchange constant for Γ$\text{}_{8}$ electrons in diluted magnetic semiconductors (DMS) and the difference in magnitude of this constant for Mn$\text{}^{2+}$ and Fe$\text{}^{3+}$ ions in HgSe.
Źródło:
Acta Physica Polonica A; 1991, 79, 1; 145-148
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Diluted Semimagnetic Semiconductor (Cd,Co)Se
Autorzy:
Cháb, V.
Mašek, J.
Orłowski, B. A.
Kowalski, B. J.
Powiązania:
https://bibliotekanauki.pl/articles/1890829.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Lp
75.50.Pp
79.60.Eq
Opis:
The electronic structure of a new semimagnetic semiconductor (Cd,Co)Se is studied by UPS and calculated by a tight-binding version of the disordered-local-moment theory. The theory accounts for the chemical disorder and for electron interactions within the Co 3d$\text{}^{7}$ shells. Both theory and experiment show Co 3d states deep in the valence band and also at the band edge. The last state seem to be responsible for unique properties of the Co-based semimagnetic semiconductors.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 333-336
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation of Magnetic Anisotropy in Bulk GaMnN:Mg Crystals
Autorzy:
Gosk, J.
Zając, M.
Kamińska, M.
Twardowski, A.
Grzegory, I.
Boćkowski, M.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2036861.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
75.30.Gw
75.50.Pp
Opis:
Magnetic properties of bulk wurtzite n-type GaMnN and highly resistive GaMnN:Mg monocrystals were studied for the magnetic field applied parallel and perpendicular to the crystal hexagonal c-axis. Magnetization of both types of samples reveals paramagnetic behavior. However, for n-type GaMnN isotropic magnetization was observed which is in agreement with Mn d$\text{}^{5}$ configuration. On the other hand, GaMnN co-doped with Mg shows large magnetic anisotropy which suggests Mn to be in nonspherical d$\text{}^{4}$ or d$\text{}^{3}$ configuration.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 665-669
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Ferromagnetic p-d Exchange in Diluted Magnetic Semiconductors
Autorzy:
Blinowski, J.
Dietl, T.
Kacman, P.
Powiązania:
https://bibliotekanauki.pl/articles/1921558.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.-m
71.70.-d
Opis:
The antiferromagnetic type of the interaction between the Γ$\text{}_{8}$-band electrons and the Mn$\text{}^{2+}$ ions in A$\text{}^{II}$B$\text{}^{IV}$ diluted magnetic semiconductors has been explained by invoking the p-d hybridization mechanism. In this paper it is shown that for particular electronic configurations of the magnetic ions in diluted magnetic semiconductors the p-d hybridization can lead to a ferromagnetic interaction between the valence-band electrons and the localized spins. This happens when all the one-electron d-orbitals which hybridize with p-band states are empty (e.g., as in Sc$\text{}^{2+}$ and Ti$\text{}^{2+}$ ions). The appropriate p-d Hamiltonian is derived and the ferromagnetic exchange constants are evaluated.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 641-644
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Properties of MnTe, ZnTe, and ZnMnTe
Autorzy:
Gonzalez Szwacki, N.
Przeździecka, E.
Dynowska, E.
Bogusławski, P.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/2038244.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Ah
75.50.Pp
61.10.-i
Opis:
Structural properties of ZnTe, MnTe, and Mn$\text{}_{1-x}$Zn$\text{}_{x}$Te alloy with zinc-blende, NiAs, and wurtzite phases were investigated by ab initio calculations. The calculated structural properties are in good agreement with the available experimental data. Theory predicts that the zinc-blende phase is more stable than wurtzite for all compositions. Mn$\text{}_{1-x}$Zn$\text{}_{x}$Te samples with 0.01 < x < 0.20 were grown by MBE. X-ray analysis of their crystalline structure revealed the presence of zinc-blende, wurtzite, and NiAs phases. The dominant phase changes from NiAs for the sample with x=0.01 to wurtzite for x=0.20. The observed stabilization of the wurtzite phase is possibly due to the hexagonal structure of the MnTe buffer.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 233-238
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Transport Properties of (III,Mn)V Ferromagnetic Semiconductors
Autorzy:
Jungwirth, T.
Sinova, J.
MacDonald, A. H.
Powiązania:
https://bibliotekanauki.pl/articles/2036882.pdf
Data publikacji:
2003-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Nr
75.30.Et
75.50.Pp
Opis:
The basic microscopic origins of ferromagnetism in (III,Mn)V compounds that have the highest transition temperatures appear to be well understood, and efficient computation methods have been developed which are able to model their magnetic, transport, and optical properties. We review some of the attempts over the past five years to achieve a theoretical under standing of these complex magnetic systems.
Źródło:
Acta Physica Polonica A; 2003, 104, 2; 103-112
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(Ga,Mn)As-based magnetic tunnel junctions under electric field from first principles
Autorzy:
Luo, M.
Shen, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1058819.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Ey
75.30.Et
75.50.Pp
Opis:
Diluted magnetic semiconductors composed in magnetic tunnel junctions have potential applications in spintronics but the development has not been fast. The main difficulty is how to control the magnetism of diluted magnetic semiconductors. For our model semiconductor magnetic tunnel junctions, (Ga,Mn)As/GaAs/(Ga,Mn)As, we found that the magnetic coupling between the transition metal ions in each diluted magnetic semiconductor electrode of such semiconductor magnetic tunnel junctions can be switched from ferromagnetic to antiferromagnetic by the external electric field. The phenomenon suggest a possible avenue for the application of semiconductor magnetic tunnel junctions.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1385-1388
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Acoustic Phonons on the Magnetic Anisotropy in GaMnAs Magnetic Semiconductors
Autorzy:
Jasiukiewicz, C.
Stagraczyński, S.
Lehmann, D.
Dugaev, V.
Berakdar, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402566.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
77.80.Fm
Opis:
We present a theoretical description of the influence of incoherent acoustic phonons on the magnetic anisotropy of magnetic semiconductors. Our theory is based on the six-band Kane model of the electron energy spectrum describing the valence band with k· p Hamiltonian including the hole-phonon interaction term. We include the effect of incoherent phonons through the hole self-energy in the six-band model, and assume a strong laser-pulse-induced flux of non-equilibrium acoustic phonons. The results of numerical calculations of magnetic anisotropy performed for (GaMn)(AsP) magnetic alloy semiconductors demonstrate the essential role of incoherent phonons.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 179-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uniaxial Strain Controlling Magnetic Anisotropy in (Ga,Mn)As
Autorzy:
Zemen, J.
Jungwirth, T.
Wunderlich, J.
Gallagher, B. L.
Powiązania:
https://bibliotekanauki.pl/articles/2047718.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
78.55.Cr
75.50.Pp
Opis:
A theoretical study of magnetocrystalline anisotropy controlled by in-plane lattice symmetry distortions is presented. The uniaxial strain, only presumed by earlier studies in order to model the observed uniaxial magnetic anisotropy, has recently become an experimentally accessible parameter. We show that the lithographically induced strain can compete with intrinsic symmetry breaking, easy axes can take general in-plane directions, and anisotropy fields scale linearly with strain for typical experimental strain magnitudes. Our results are in qualitative agreement with experimental results.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 431-435
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Local Potential on Exciton Splitting in Highly Diluted Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
Autorzy:
Kłopotowski, Ł.
Herbich, M.
Mac, W.
Stachow-Wójcik, A.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1968234.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Dg
75.50.Pp
71.70.Gm
Opis:
We investigated magnetoreflectance and magnetization of highly diluted bulk Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te crystals 0.2% ≤ x ≤ 10%. The exchange constant in terms of mean field approximation and virtual crystal approximation (the ratio of the heavy hole exciton splitting to mean spin per unit cell) was evaluated and found x-dependent. This deviation from the mean field approximation and virtual crystal approximation prediction is caused by the local potential introduced by Mn ions. We discuss the problem within a Wigner-Seitz approach and within a model of magnetic and chemical disorder based on the alloy theory.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 837-840
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of Raman Scattering by Magnons in Bulk-Like MBE-Gwn MnTe Films
Autorzy:
Szuszkiewicz, W.
Mohrange, J. F.
Jouanne, M.
Kanehisa, M. A.
Świrkowicz, R.
Dynowska, E.
Janik, E.
Wojtowicz, T.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1968436.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Ds
75.50.Pp
78.30.-j
Opis:
Temperature dependence of the magnon frequency was studied for cubic MnTe epilayers by the Raman scattering measurements. Experimental data are compared to the results of theoretical calculations performed within the framework of the Heisenberg model using Green's function formalism.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1025-1028
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetotransport and Magnetic Properties of (Ga,Mn)As and its Heterostructures
Autorzy:
Ohno, H.
Powiązania:
https://bibliotekanauki.pl/articles/1968989.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Ey
75.50.Pp
75.70.Cn
Opis:
Introduction of high density of Mn in GaAs by low temperature molecular beam epitaxy results in a homogeneous diluted magnetic semiconductor (Ga,Mn)As, which exhibits ferromagnetism at low temperatures. Temperature and magnetic field dependence of magnetotransport and magnetization of (Ga,Mn)As films revealed the Curie temperature T$\text{}_{C}$ which can be as high as 110 K and the p-d exchange, which explains T$\text{}_{C}$ in the framework of the RKKY interaction. Multilayer heterostructures such as all-semiconductor ferromagnet/nonmagnet/ferromagnet trilayer structures and resonant tunneling diodes have been fabricated and studied. These heterostructure results show the potential of the present material system for exploring new physics and for developing new functionality toward future electronic and optical devices.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 155-164
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pecularities of p-d Interaction in Semimagnetic Semiconductors with Cr$\text{}^{2+1}$
Autorzy:
Blinowski, J.
Kacman, P.
Powiązania:
https://bibliotekanauki.pl/articles/1890686.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.-m
71.70.-d
Opis:
In cubic DMS crystals with Cr$\text{}^{2+}$ content the non-Heisenberg part of the p-d interaction together with the strong, static Jahn-Teller effect may lead to a zero-magnetic field splitting and significant modifications of the spin splittings for the valence band. The effect reaches a maximum when all Jahn-Teller distortions are oriented along one of the [100]-type crystallographic directions.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 295-297
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of ZMTO Alloys
Autorzy:
Avdonin, A.
Knoff, W.
Gałązka, R.
Powiązania:
https://bibliotekanauki.pl/articles/1791348.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
75.50.Pp
75.60.Ej
Opis:
The results of the magnetization and photoluminescence measurements of the ZMTO are presented. Under field cooling conditions a phase transition is observed. The dependence of the temperature of transition on oxygen concentration is analyzed. A model is proposed.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 916-917
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Epitaxial Fe/(Ga,Mn)As Hybrids
Autorzy:
Kalbarczyk, K.
Dziatkowski, K.
Szczytko, J.
Gosk, J.
Tokarczyk, M.
Kowalski, G.
Twardowski, A.
Bednarski, W.
Ostrowski, A.
Waplak, S.
Martinek, J.
Liu, X.
Furdyna, J.
Powiązania:
https://bibliotekanauki.pl/articles/1399140.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.-c
75.30.Gw
75.50.Pp
75.50.Bb
Opis:
Thin-film structures composed of two kinds of ferromagnetic material - metallic Fe and semiconducting (Ga,Mn)As - were investigated by means of SQUID magnetometry and ferromagnetic resonance spectroscopy. Dependence of remnant magnetic moment on temperature showed unexpected anisotropic features when recorded along two orthogonal in-plane directions. For one of these orientations, the change in sign of the slope of m(T) curve at the Curie point of (Ga,Mn)As was observed, while for the other, an analogous m(T) curve retained monotonic character. Based on the comparison with ferromagnetic resonance data, the apparent non-monotonicity was attributed to the temperature-induced change of balance between the external magnetic field and uniaxial magnetic anisotropy in the plane of Fe layer.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 873-876
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role of Frustration in Magnetism of Ge$\text{}_{1-x}$Cr$\text{}_{x}$Te Semimagnetic Semiconductor
Autorzy:
Kilanski, L.
Górska, M.
Dobrowolski, W.
Arciszewska, M.
Domukhovski, V.
Anderson, J. R.
Butch, N. P.
Podgórni, A.
Slynko, V. E.
Slynko, E. I.
Powiązania:
https://bibliotekanauki.pl/articles/2048082.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.40.Gb
75.50.Lk
75.50.Pp
Opis:
We present preliminary studies of magnetic properties of Ge$\text{}_{1-x}$Cr$\text{}_{x}$Te semimagnetic semiconductors with low chromium content x < 0.026. The static and dynamic magnetometry techniques were employed for the current investigations. The obtained results showed large bifurcations between zero-field cooled and field cooled magnetization curves at temperatures lower than 50 K. The dynamic susceptibility measurements proved via frequency shifting of the peaks that the observed magnetic order at low temperatures was the spin-glass-like state caused by magnetic frustration of the system.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 654-656
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Magneto-Transport Characterization of (Ga,Mn)(Bi,As) Epitaxial Layers
Autorzy:
Levchenko, K.
Andrearczyk, T.
Domagala, J.
Wosinski, T.
Figielski, T.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1195381.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
73.50.Jt
85.75.-d
Opis:
High-quality layers of the (Ga,Mn)(Bi,As) quaternary compound semiconductor have been grown by the low-temperature molecular-beam epitaxy technique. An effect of Bi incorporation into the (Ga,Mn)As ferromagnetic semiconductor and the post-growth annealing treatment of the layers have been investigated through examination of their magnetic and magneto-transport properties. Significant enhancement of the planar Hall effect magnitude upon addition of Bi into the layers is interpreted as a result of increased spin-orbit coupling in the (Ga,Mn)(Bi,As) layers.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1121-1124
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model for the Surface Anisotropy Field Observed in Spin-Wave Resonance in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/1386858.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
Opis:
In this study we show why spin-wave resonance in a (Ga,Mn)As thin film may, in different conditions, meet the assumptions of either the surface inhomogeneity (SI) or the volume inhomogeneity (VI) model.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 508-510
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magneto-Transport Characterization of Four-Arm Nanostructure Based on Ferromagnetic (Ga,Mn)As
Autorzy:
Andrearczyk, T.
Wosiński, T.
Figielski, T.
Mąkosa, A.
Tkaczyk, Z.
Łusakowska, E.
Wróbel, J.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1811912.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.50.Jt
75.50.Pp
75.30.Gw
75.60.Ch
Opis:
We report on results of magneto-transport measurements performed on four-arm nanostructure fabricated from p-type ferromagnetic $Ga_{0.92}Mn_{0.08}As$ layer. The results reveal hysteresis-like behaviors of low field magnetoresistance. We interpret the magnetoresistance in terms of domain walls, which are expected to be trapped inside the nanostructure at some particular positions and which contribute to the total resistance.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1049-1054
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetism in II-VI Based Semiconductor Structures
Autorzy:
Cibert, J.
Ferrand, D.
Tatarenko, S.
Wasiela, A.
Kossacki, P.
Dietl, T.
Powiązania:
https://bibliotekanauki.pl/articles/2027470.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
75.50.Pp
75.30.Hx
75.50.Dd
Opis:
The experimental results on carrier-induced ferromagnetic interaction in II-VI diluted magnetic semiconductors are shortly reviewed and analyzed in the light of the mean field approximation. We particularly take the point of view of the experimentalist to emphasize (i) points which are easily understood within this simple model (as the role of the detailed structure of the valence band) and hence should be incorporated into more sophisticated models, and (ii) points which are not taken into account in the mean field model (e.g., disorder effects) and hence call for more elaborate descriptions. We particularly discuss the case of a low carrier density, and show that the situation appears as experimentally very different in the highly disordered 3D layers and in the modulation doped 2D quantum wells.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 227-236
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-100 z 196

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