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Tytuł:
A Comparison of the Valence Band Structure of Bulk and Epitaxial GeTe-based Diluted Magnetic Semiconductors
Autorzy:
Pietrzyk, M.
Kowalski, B.
Orlowski, B.
Knoff, W.
Story, T.
Dobrowolski, W.
Slynko, V.
Slynko, E.
Johnson, R.
Powiązania:
https://bibliotekanauki.pl/articles/1538868.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.-i
71.20.Mq
71.20.Be
Opis:
In this work we present a comparison of the experimental results, which have been obtained by the resonant photoelectron spectroscopy for a set of selected diluted magnetic semiconductors based on GeTe, doped with manganese. The photoemission spectra are acquired for the photon energy range of 40-60 eV, corresponding to the Mn 3p → 3d resonances. The spectral features related to Mn 3d states are revealed in the emission from the valence band. The Mn 3d states contribution manifests itself in the whole valence band with a maximum at the binding energy of 3.8 eV.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 293-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of Electrical Properties of Hg$\text{}_{1-x}$Zn$\text{}_{x}$Se upon Doping with Fe
Autorzy:
Dobrowolski, W.
Grodzicka, E.
Kossut, J.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1921589.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
72.20.Fr
71.55.Fr
Opis:
Results of measurements of electron concentration and mobility in mixed crystals of Hg$\text{}_{1-x}$Zn$\text{}_{x}$Se (0 ≤ x ≤ 0.07) doped with resonant Fe donors (0 ≤ n$\text{}_{Fe}$ ≤ 5 × 10$\text{}^{19}$ cm$\text{}^{-3}$) at liquid helium temperatures are presented. The data show that there is a considerable improvement of the electrical properties of the material when Fe impurities are present. The analysis of the mobility in terms of the scattering from ionized centers (accounting for possible spatial correlation of impurity charges) and the alloy scattering is in agreement with the measured data.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 681-684
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:
Anomalous Hall Effect in IV-VI Semiconductors
Autorzy:
Dyrdał, A.
Dugaev, V.
Barnaś, J.
Brodowska, B.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1810533.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
75.50.Pp
72.25.Dc
Opis:
We consider theoretically the topological contribution to the anomalous Hall effect in narrow-gap IV-VI magnetic semiconductors in which the relativistic terms are relatively large and determine both the non-parabolicity of the energy spectrum and strong spin-orbit interaction. We use the relativistic Dirac model and linear response theory to calculate this contribution. Experimental data on the anomalous Hall effect in these compounds are also presented and discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 287-289
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Peculiarities of Electron Transport in PbTe:Cr due to Presence of Resonant Impurity State
Autorzy:
Grodzicka, E.
Dobrowolski, W.
Kossut, J.
Story, T.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1929686.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Fr
72.10.Fk
72.80.Jc
Opis:
The results of transport investigation of Pb$\text{}_{1-x}$Cr$\text{}_{x}$Te (x ≤ 0.009) in temperature range 3.5-300 K are presented. The obtained electron concentration and electron mobility vs. temperature and Cr concentration data are interpreted and discussed within the model assuming that Cr in PbTe forms a donor state resonant with the conduction band.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 599-603
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:
Pressure Study of Charged Donor Ordering in HgSe Doped with Iron and Gallium
Autorzy:
Skierbiszewski, C.
Suski, T.
Kossut, J.
Wilamowski, Z.
Dobrowolski, W.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1891020.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Fk
72.20.Fr
72.80.Jc
Opis:
Transport experiments (Hall effect and conductivity) under hydrostatic pressure up to 1 GPa at liquid helium temperatures on HgSe: Fe, Ga (N$\text{}_{Fe}$ = 2 x 10$\text{}^{19}$ cm$\text{}^{-3}$; 0 ≤ N$\text{}_{Ga}$ ≤ 10$\text{}^{19}$ cm$\text{}^{-3}$) were performed. The results show that the gallium co-doping of HgSe:Fe decreases the degree of spatial correlations between charged impurities. Under the hydrostatic pressure, used as a tool for changing the ratio of the charged to neutral impurities, this effect is even more pronounced. A qualitative agreement between the calculation within the short-range correlation model and our experimental data is achieved.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 401-404
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:
Anomalous Hall Effect in $Ge_{1-x-y}Pb_{x}Mn_{y}Te$ Composite System
Autorzy:
Podgórni, A.
Kilanski, L.
Dobrowolski, W.
Górska, M.
Domukhovski, V.
Brodowska, B.
Reszka, A.
Kowalski, B.
Slynko, V.
Slynko, E.
Powiązania:
https://bibliotekanauki.pl/articles/1376191.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.J-
72.80.Ga
75.40.Mg
75.50.Pp
Opis:
The purpose of this study was to investigate the magnetotransport properties of the $Ge_{0.743}Pb_{0.183}Mn_{0.074}Te$ mixed crystal. The results of magnetization measurements indicated that the compound is a spin-glass-like diluted magnetic semiconductor with critical temperature $T_{SG}$=97.5 K. Nanoclusters in the sample are observed. Both, matrix and clusters are magnetically active. Resistivity as a function of temperature has a minimum at 30 K. Below the minimum a variable-range hopping is observed, while above the minimum a metallic-like behavior occurs. The crystal has high hole concentration, p=6.6×$10^{20}$ $cm^{-3}$, temperature-independent. Magnetoresistance amplitude changes from -0.78 to 1.18% with increase of temperature. In the magnetotransport measurements we observed the anomalous Hall effect with hysteresis loops. Calculated anomalous Hall effect coefficient, $R_{S}$ = 2.0×$10^{6}$ $m^{3}$/C, is temperature independent. The analysis indicates the extrinsic skew scattering mechanism to be the main physical mechanism responsible for anomalous Hall effect in $Ge_{0.743}Pb_{0.183}Mn_{0.074}Te$ alloy.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1180-1183
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Magnetic Field on Fine Structure of Tunnel Current in Double-Barrier Resonant-Tunneling Devices
Autorzy:
Belyaev, A. E.
Vitusevich, S. A.
Glavin, B. A.
Mąkosa, A.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1933716.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
An effect of magnetic field on a fine oscillatory structure revealed in the resonant current flowing through double-barrier resonant-tunneling devices is examined. It is found that the observed variation of the fine structure in a magnetic field parallel to the current direction differs considerably from that appearing in tunnel current flowing through single-barrier structures. Experimental results are explained in terms of the quantum interference effect arising in structures having wide spacer layers.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 675-678
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PbSe:Cr - New Resonant Donor System
Autorzy:
Story, T.
Wilamowski, Ż.
Grodzicka, E.
Dobrowolski, W.
Witkowska, B.
Voiron, J.
Powiązania:
https://bibliotekanauki.pl/articles/1932086.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pρ
72.20.My
Opis:
Hall effect, conductivity, electron paramagnetic resonance and magnetization of Pb$\text{}_{1-x}$Cr$\text{}_{x}$Se (x ≤ 0.01) crystals were measured as a function of Cr content and electron concentration. The experimental results suggest that Cr in PbSe creates a resonant donor state with the energy of about 125 meV above the bottom of the conduction band.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 229-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Susceptibility of Cd$\text{}_{1-x}$Fe$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$
Autorzy:
Arciszewska, M.
Mycielski, A.
Dobrowolski, W.
Lenard, A.
Mauger, A.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1890693.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
75.20.Hr
75.30.Cr
Opis:
Magnetic susceptibility of Cd$\text{}_{1-x}$Fe$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ was found to consist of Van Vleck term (characteristic for the Fe$\text{}^{2+}$ centers in tetrahedral crystal symmetry) and temperature-dependent contribution. The occurrence of the latter indicates an existence of additional magnetic moments. We ascribe their origin to the modification of the Fe$\text{}^{2+}$ energy level spectrum induced by mixed Te-Se anion environment.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 303-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Luminescent Properties of ZnTe-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ Heterojunction
Autorzy:
Le Van, Khoi
Dobrowolski, W.
Witkowska, B.
Mycielski, A.
Galązka, R. R.
Nguyen, Khoi
Powiązania:
https://bibliotekanauki.pl/articles/1872527.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Fi
Opis:
ZnTe-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ heterojunctions were prepared by vapor-transport epitaxy of ZnTe on In-doped Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ (x = 0.05, y = 0.03) single crystalline substrate in vacuum. At temperatures lower than 120 K the infrared and red electroluminescence were observed from the ZnTe-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ diode with forward current density in the range 0.003-4.0 A/cm$\text{}^{2}$.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 325-328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photovoltaic Effect of ZnTe-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ Heterojunctions in Presence of Magnetic Field
Autorzy:
Gałązka, R. R.
Nguyen, The Khoi
Khoi, Le Van
Dobrowolski, W.
Witkowska, B.
Mycielski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1933917.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.25.Tn
78.20.Ls
72.80.Ga
Opis:
Photovoltaic effect of the ZnTe-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ heterojunctions, prepared by vapor-transport epitaxy of ZnTe on Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ substrate was studied. The photovoltaic measurements were carried out over the temperature range from 12 K to 300 K and in the magnetic field up to 6 T. In the magnetic field, maximum of the sensitivity corresponding to the energy of the forbidden gap of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ substrate splits into two components for σ$\text{}^{+}$ and σ¯ circular polarizations of incident light. This phenomenon was ascribed to the exchange interaction of the magnetic moments of Mn$\text{}^{++}$ ions with band electrons. From the value of the splitting energy the exchange integral N$\text{}_{0}$(α-β) was determined to be 1.15 ± 0.2 eV.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 841-844
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Scattering from ZnO(Fe) Nanoparticles
Autorzy:
Romčević, N.
Kostić, R.
Romčević, M.
Hadžić, B.
Kuryliszyn-Kudelska, I.
Dobrowolski, W.
Narkiewicz, U.
Sibera, D.
Powiązania:
https://bibliotekanauki.pl/articles/1811980.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.-e
78.30.Fs
78.67.-n
Opis:
Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine composition of the samples (ZnO, Fe₂O₃, ZnFe₂O₄) and the mean crystalline size (8-52 nm). In this paper we report the experimental spectra of the Raman scattering (from 200 to $1600 cm^{-1}$). Main characteristics of experimental Raman spectrum in 200 to $1600 cm^{-1}$ spectral region are: sharp peak at $436 cm^{-1}$ and broad two-phonon structure at ≈ $1150 cm^{-1}, typical of ZnO;broad structure below $700 cm^{-1}$ that has different position and shape in case of ZnFe₂O₄ or Fe₂O₃ nanoparticles.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1323-1328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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