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Wyszukujesz frazę "75.50.-" wg kryterium: Temat


Tytuł:
Magnetoresistance and Magnetic Properties of the Double Perovskites
Autorzy:
Philipp, J. B.
Majewski, P.
Reisinger, D.
Geprägs, S.
Opel, M.
Erb, A.
Alff, L.
Gross, R.
Powiązania:
https://bibliotekanauki.pl/articles/2037043.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Cc
75.50.Ss
Opis:
The magnetic double perovskite materials of composition A$\text{}_{2}$BB'O$\text{}_{6}$ with A an alkaline earth ion and B and B' a magnetic and non-magnetic transition metal or lanthanide ion, respectively, have attracted considerable attention due to their interesting magnetic properties ranging from antiferromagnetism to geometrically frustrated spin systems and ferromagnetism. With respect to application in spin electronics, the ferromagnetic double perovskites with BB'= CrW, CrRe, FeMo, or FeRe and A = Ca, Ba, Sr are highly interesting due to their in most cases high Curie temperatures well above room temperature and their half-metallic behavior. Here, we summarize the structural, magnetotransport, magnetic, and optical properties of the ferromagnetic double perovskites and discuss the underlying physics. In particular, we discuss the impact of steric effects resulting in a distorted perovskite structure, doping effects obtained by a partial replacing of the divalent alkaline earth ions on the A site by a trivalent lanthanide as well as B/B' cationic disorder on the Curie temperature T$\text{}_{C}$, the saturation magnetization and the magnetotransport properties. Our results support the presence of a kinetic energy driven mechanism in the ferromagnetic double perovskites, where ferromagnetism is stabilized by a hybridization of states of the non-magnetic B'-site positioned in between the high spin B-sites.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 7-26
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Phase Diagram of Zinc-Blende Cd$\text{}_{1-x}$Mn$\text{}_{x}$Se
Autorzy:
Sawicki, M.
Furdyna, J. K.
Luo, H.
Powiązania:
https://bibliotekanauki.pl/articles/1952079.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Rr
75.50.Lk
Opis:
The paper reports first magnetic measurements performed on MBE grown epilayers of zinc-blende Cd$\text{}_{1-x}$Mn$\text{}_{x}$Se. For all samples studied in the concentration range 0.24 < x < 0.63 we find at low temperatures a history-dependent magnetic response, suggesting a transition to a spin-glass-like state. The central result of the paper is the presentation of a new, complete magnetic phase diagram for this material.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 923-926
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Al and Cu Additions on Microstructure and Magnetic Properties of NdTb-FeCo-B Magnets
Autorzy:
Sadullahoğlu, G.
Altuncevahir, B.
Addemir, O.
Powiązania:
https://bibliotekanauki.pl/articles/1365124.pdf
Data publikacji:
2014-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ww
75.50.Vv
75.50.Bb
Opis:
With the addition of Al and/or Cu into the NdFeB based magnet, the soft free iron phase was not observed in the cast alloys while it exists in the microstructure of the undoped NdFeB ingots. For the undoped sample, free iron disappeared after hot deformation process. Grain orientation is not good and there are deviations in the growth direction of the lamellar grains which are not perpendicular to the pressing direction. On the other hand, there is a striking change that the intergranular chemistry of Al added ingot separated into Nd-rich phase and a ternary FeNdAl composition most probably formed at the pressing temperature of 750°C. The highest remanent magnetization of 7.47 kG obtained for this sample, it might be due to the hard magnetic properties of this ternary composition. For the Al-Cu added sample, the high $H_{c}$ and $B_{r}$ values of 7.71 kOe and 7.33 kG, respectively, can be attributed to the homogeneous distribution of the intergranular composition and good orientation of the magnetic grains by hot deformation process.
Źródło:
Acta Physica Polonica A; 2014, 125, 5; 1172-1175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Search for Dimensionality Crossover of Spin-Glass Freezing in Superlattices of Cd$\text{}_{0.50}$Mn$\text{}_{0.50}$Te/CdTe
Autorzy:
Sawicki, M.
Dietl, T.
Karczewski, G.
Wojtowicz, T.
Kossut, J.
Skośkiewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1952078.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Rr
75.50.Lk
Opis:
SQUID measurements of the time decay of the thermoremanent magnetization (field-cooled in 1000 Oe) at long time scale, 10$\text{}^{2}$ < t < 10$\text{}^{5}$ s, are presented for MBE grown Cd$\text{}_{0.50}$Mn$\text{}_{0.50}$Te. We found that for both thin (32 Å) and thick (2500 Å) layers the spin-glass dynamics is characterized by a similar value of k = -(1/T$\text{}_{f}$)(dT$\text{}_{f}$/dlogt) > 0.05, indicating the absence of the phase transition at nonzero temperature under the experimental conditions.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 919-922
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Characterization of Molecular Beam Epitaxy Grown $Cd_{1-x}$Mn$\text{}_{x}$Te Structures
Autorzy:
Sawicki, M.
Kolesnik, S.
Wojtowicz, T.
Karczewski, G.
Janik, E.
Kutrowski, M.
Żakrzewski, A.
Dynowska, E.
Dietl, T.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1931934.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Rr
75.50.Ee
Opis:
The paper reports on the application of SQUID magnetometry to probe magnetic ion distribution in epilayers and at interfaces of diluted magnetic semiconductors. We present also new results on the possible influence of the magnetic confinement on the formation of the spin-glass phase, and on antiferromagnetic phase transition in zinc-blende MnTe.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 169-172
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Grain Boundary Compositions and Magnetic Properties of Hot-Worked $Nd_{18}Tb_1Fe_{66.5}Co_5Al_{1.5}B_8$ Magnets
Autorzy:
Sadullahoğlu, G.
Altuncevahir, B.
Okan Addemir, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399702.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ww
75.50.Vv
75.50.Bb
Opis:
Magnetic properties which are related to the compositions on the grain boundaries of the NdFeB permanent magnets were studied at different hot working temperatures applied to the cast $Nd_{18}Tb_1Fe_{66.5}Co_5Al_{1.5}B_8$ ingots. Since the addition of Al caused the formation of hard magnetic μ phase between the magnetic NdFeB crystals after the pressing 800C $H_{c}$ value increased to the highest value of 8.21 kOe. According to the SEM micrographs and EDS analysis, the increase in pressing temperature, the atomic ratios in the NdFeAl compositions approached to hard magnetic μ phase with the increase in pressing temperature and its exact composition was obtained in the sample hot deformed at 800°C. Although the secondary μ phase with a high melting temperature is detremental to the alignment of c axis of the magnetic NdFeB grains along the pressing direction, we found that the magnetic properties of the magnets improve due to the presence of this hard magnetic phase on the grain boundaries.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 233-234
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Transition Metal Molybdates
Autorzy:
Konieczny, P.
Pełka, R.
Grzesiak-Nowak, M.
Szymańska, A.
Łasocha, W.
Wasiutyński, T.
Powiązania:
https://bibliotekanauki.pl/articles/1368631.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
75.50.Ee
75.50.-y
Opis:
Two examples of transition metal molybdates were studied with the use of X-ray diffraction and DC magnetometry techniques. First compound, copper dimolybdate trihydrate $CuMo_{2}O_{7}$·$3H_{2}O$ contains 2D layers. The second one is fibrillar cobalt trimolybdate octahydrate $CoMo_{3}O_{10}$·$8H_{2}O$. Both compounds exhibit paramagnetic behaviour at room temperature. However, in the first one copper ions form dimers linked by oxygen bridges, in which exchange interactions between two localized spin states occur. The second compound consists of isolated cobalt ions in the octahedral surroundings, resulting in magnetic properties deviating from the Curie law.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 250-251
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-ray Reflectivity and Polarized Neutron Reflectivity Investigations of $[Co_{60}Fe_{60}B_{20}//MgO]_n$ Multilayers
Autorzy:
Vadalà, M.
Wolff, M.
Westerholt, K.
Zabel, H.
Wisniowski, P.
Cardoso, S.
Powiązania:
https://bibliotekanauki.pl/articles/1814030.pdf
Data publikacji:
2007-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-i
75.50.Kj
75.50.Cc
Opis:
In recent years magnetic tunnel junctions have been intensively studied and incorporated in magnetic random access memory devices and magnetic sensors, where large tunnelling magnetoresistance ratios are preferred. The largest tunnelling magnetoresistance values until now have been observed in magnetic tunnel junctions with MgO barriers and CoFeB electrodes after annealing of the junction above the recrystallization temperature of the amorphous CoFeB layers. We used X-ray reflectivity and polarized neutron reflectivity to study [Co_{60}Fe_{60}B_ {20}//MgO]_{x14} multilayers with the MgO layers prepared by different methods and annealed at different temperatures in order to compare the interface quality and the structural changes induced upon annealing.
Źródło:
Acta Physica Polonica A; 2007, 112, 6; 1249-1257
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetization Reversal Processes in Pr-Fe-B-type Nanocrystalline Magnets
Autorzy:
Pawlik, K.
Pawlik, P.
Kaszuwara, W.
Wysłocki, J.
Powiązania:
https://bibliotekanauki.pl/articles/1368000.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Vv
75.60.Ej
75.50.Bb
75.50.Tt
75.50.Ww
Opis:
The magnetization reversal processes in magnets derived from rapidly solidified $Pr_{9}Fe_{52}Co_{13}Zr_{1}Nb_{4}B_{21}$ alloy samples were studied by analysis of minor hysteresis loops and recoil curves. The studies were carried out on suction-cast 1 mm diameter rod, 1 mm thick plate, 3 mm outer diameter (o.d.) tube and melt-spun ribbon samples subjected to annealing at 983 K for 5 min. The X-ray diffraction analysis has shown multiphase constitution of the samples. Structural and magnetic studies indicated that the initial state of microstructure and phase composition affects the magnetization reversal processes in annealed samples due to a variation of microstructure in samples of various shapes. Magnetic studies allowed estimation of the mean values of nucleation and pinning fields that control the magnetization reversal processes.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 186-187
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Coercivity FePt Nanoparticle Assemblies Embedded in Oxide-Matrix by Atomic Layer Deposition
Autorzy:
Kong, J.
Li, A.
Gao, M.
Yan, Q.
Wu, D.
Powiązania:
https://bibliotekanauki.pl/articles/1399662.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Vv
75.75.Cd
75.50.Bb
75.50.Ss
Opis:
Self-assembled face-centered cubic FePt nanoparticles were embedded into the oxide capping layer using the atomic layer deposition technology. The effect of the oxide-matrix layer on the structure, mono-dispersibility, and magnetic properties of the FePt/oxide composite thin films was investigated. Experimental results suggest that the protection of the oxide-matrix capping layer can effectively inhibit the grain growth and particle aggregation, and preserve the ordered domains of the FePt nanoparticles during the L 1_0 ordering transition through annealing. The combination of the atomic layer deposition capping layer and self-assembled FePt nanoparticles provides a new potential approach to fabricate the ultrahigh-density magnetic recording media.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 173-176
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Compensation Model of Magnetic Circuits with Modern Magnetic Materials
Autorzy:
Szumiata, T.
Gzik-Szumiata, M.
Powiązania:
https://bibliotekanauki.pl/articles/1388066.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ww
75.50.Vv
75.50.Kj
75.50.Bb
07.55.Db
Opis:
In this work a quantitative analysis of thermal compensation has been performed for a magnetic circuit producing magnetic field in the air gap. The considered system consists of Sm₃Co₁₇ type permanent magnet (as a source of magnetic field), nanocrystalline FINEMET alloy (as ultra-soft magnetic medium) and Fe-Ni low Curie temperature compensative material (as a magnetic shunt). Distribution of magnetic field induction in the circuit has been calculated numerically within standard one-dimensional approximation, considering nonlinearities of compensative material as well as demagnetization susceptibility of permanent magnet. It has been theoretically predicted, that an appropriate choice of the compensative element thickness improves significantly thermal stability of magnetic field in the air gap.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 650-652
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Relaxation and Memory Effect in Nickel-Chromium Cyanide Nanoparticles
Autorzy:
Zentko, A.
Kavečanský, V.
Mihalik, M.
Maťaš, S.
Mitróová, Z.
Zentková, M.
Maryško, M.
Jagličić, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1813858.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
75.50.Lk
Opis:
The low temperature dynamics of a magnetic nanoparticle system $Ni_3[Cr(CN)_6]_2$ with an average nanoparticles size of 4 nm was studied. Using different temperature and field protocols memory phenomena were studied by the DC magnetization and magnetic relaxation measurements of the system at temperatures below $T_m$ = 19 K. Aging experiments show an absence of any waiting time dependence in the magnetization relaxation due to a field change after zero field and field cooling. This observation discriminates the dynamics of the system from the behaviour of a classical spin-glass.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 511-514
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Zinc Doped Ferrites
Autorzy:
Abd El-Ati, M. I.
Kafafy, Aziz M.
Tawfik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1887816.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Dd
Opis:
A series of samples of the system Co$\text{}_{1-x}$Zn$\text{}_{x}$Fe$\text{}_{2}$O$\text{}_{4}$ (x = 0.0, 0.3, 0.4, 0.5 and 0.8) have been prepared by the usual ceramic technique. X-ray analysis shows that they are cubic spinel (single phase). The lattice parameter a and the bulk density D are measured for the samples. The substitution experiments replacing Co$\text{}^{2+}$ by Zn$\text{}^{2+}$ furnish new significant fact concerning the magnetic behaviour of ferrites. The magnetic strength of the magnetic ions on the Band A-sites can be varried relative to each other by the substitution of Zn$\text{}^{2+}$. The increase of density of the composition increases the magnetic interaction of the dipole moment at the B-sites.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 889-894
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 Vanadium Substitution of Cobalt in $NdCo_2Si_2$
Autorzy:
Chowdhury, R.
Dhara, S.
Bandyopadhyay, B.
Powiązania:
https://bibliotekanauki.pl/articles/1402070.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
75.50.Gg
75.50.Ee
75.50.Cc
75.50.Dd
Opis:
In NdCo₂Si₂, partial substitution of Co by V having a larger atomic radius results in negative pressure affecting the magnetic properties of the compound. The samples $Nd(Co_{1-x}V_{x})_Si_2$ (x=0, 0.20, 0.35) have been prepared and characterized using X-ray diffraction. The parent compound NdCo₂Si₂ is antiferromagnetic with $T_{N}$ of 34 K whereas the temperature dependence of inverse susceptibility in the doped samples show ferrimagnetic behaviour below 45 K. From the magnetic field dependence of magnetization and the coercive fields obtained from hysteresis loops, the doped samples exhibit ferromagnetism below ≈ 20 K. The specific heat studies compare the magnetic transitions in the parent and doped samples. $Nd(Co_{0.65}V_{0.35})_2Si_2$ shows a magnetoresistance of 15% at 4 K.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 530-532
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Temperature and Time of Stress Annealing on Magnetic Properties of Amorphous Microwires
Autorzy:
Chichay, K.
Rodionova, V.
Ipatov, M.
Zhukova, V.
Zhukov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1387552.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
75.50.Cc
75.50.Kj
75.60.Ej
Opis:
In this work we studied influence of time and temperature of stress annealing on magnetic properties of amorphous Co-based and CoFeNi-based microwires. We showed that this type of treatment can be very effective for manipulation of magnetic properties of amorphous ferromagnetic glass-coated microwires. Co-based microwires keep S-shape hysteresis loop after any annealing. Annealing of Co-based microwires at different conditions allows tailoring of the saturation field. CoFeNi-based microwires present either S-shape or rectangular shape of the hysteresis loops depending on the value of the axial stress during the annealing. We demonstrated the possibility to change the switching field of microwires with acquired bistability in the range from 0.5 to 25 A/m.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 600-602
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Search for Dimensional Effects in Spin-Glass Transition in Thin Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Multilayers
Autorzy:
Sawicki, M.
Dietl, T.
Skośkiewicz, T.
Karczewski, G.
Wojtowicz, T.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1943818.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Rr
75.50.Lk
75.30.Kz
75.50.-y
Opis:
SQUID magnetic measurements of CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te, x ≃ 0.5, multi-layers with different CdMnTe layer thickness w reveal the persistence of the spin-glass irreversibilities down to ≃ 16 Å thin layers, i.e., well beyond the previously postulated 40 Å as a quasi-2D threshold. The freezing temperature T$\text{}_{f}$ is found to be a monotonic function of w, and it obeys a scaling law T$\text{}_{f}$ ∝ w$\text{}^{a}$, with a 0.8 similar to that for canonical spin-glasses. Magnetic properties of all studied structures are found to be independent of the orientation of the magnetic field.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 1038-1042
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 Properties in Mn Pure Powder
Autorzy:
Szlaferek, A.
Baszyński, J.
Waplak, S.
Jóźwiak, K.
Powiązania:
https://bibliotekanauki.pl/articles/1964612.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Tt
Opis:
The structural and magnetic properties of deformed powder of Mn obtained by mechanical grinding have been investigated using X-ray diffraction and magnetic measurements. The small values of ferromagnetic moment of Mn after grinding are attributed to the formation of a deformed phase at the surface of grains with enlargement of the interatomic spacings at the grains boundaries.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 311-314
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:
Magnetic Behaviour of Core/Shell Nanoparticle Assemblies: Interparticle Interactions Effects
Autorzy:
Trohidou, K.
Vasilakaki, M.
Powiązania:
https://bibliotekanauki.pl/articles/1539059.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
75.40.Mg
75.50.Bb
75.50.Vv
75.30.Et
75.60.Ej
75.50.Lk
75.50.Cc
75.50.Ss
75.75.+a
Opis:
Interparticle interactions in assemblies of nanoparticles represent an important effect that modifies their magnetic behavior. The characteristics of the hysteresis loop and the temperature dependent magnetization (field cooled (FC)/zero-field cooled (ZFC)) are studied numerically in magnetic nanoparticle assemblies using Monte Carlo simulations and the standard Metropolis algorithm. We study composite spin nanostructures with ferromagnetic (FM) core/antiferromagnetic (AFM) shell morphology and simple ferromagnetic nanostructures. Both three-dimensional granular solids and two-dimensional ordered nanoparticle arrays are analyzed and compared, with emphasis on the interplay between single-particle characteristics and magnetostatic interparticle interactions. We find that the antiferromagnetic interface provides a strong exchange coupling with the ferromagnetic core and, through it, an effective long range interparticle correlation, modified from that of simple FM nanostructures. The results of our simulations are compared with experimental findings.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 374-378
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Vitrovac Content on Magnetic Properties in Composite Materials Based on the Mixture of Two Ferromagnets
Autorzy:
Hegedűs, L.
Kollár, P.
Füzer, J.
Bureš, R.
Fáberová, M.
Kurek, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032700.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
75.50.Cc
75.50.Kj
75.60.-d
Opis:
Soft magnetic composite materials play an important role in nowadays industry, replacing the traditional materials such as electrical steels and soft ferrites, especially at medium and higher frequency applications. The material can be tailored for a specific application by changing the composition of the material and by adaptation of the fabrication process. The aim of this work was to investigate the morphology, phase composition and magnetic properties of soft magnetic composite materials with various magnetic content to minimize the total magnetic losses. The prepared sample series was based on the mixture of two different ferromagnets Vitrovac 6155 and Somaloy 700 without addition of insulating material. The samples were prepared by conventional powder metallurgy with particular fraction of Vitrovac in the form of a ring for magnetic measurements in AC fields and electric resistivity measurements. The samples with 5 wt% and 20 wt% fractions of Vitrovac exhibit lower values of total losses in comparison with Somaloy heat treated at 530°C.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 765-767
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tailoring of Magnetic Properties and Magnetoimpedance Effect in Thin Amorphous Wires
Autorzy:
Zhukov, A.
Talaat, A.
Ipatov, M.
Blanco, J.
Zhukova, V.
Powiązania:
https://bibliotekanauki.pl/articles/1398754.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
75.50.Cc
75.50.Kj
75.60.Ej
Opis:
We have studied the effect of annealing conditions on magnetic properties of amorphous CoFeNi-based glass-coated microwires. We show that annealing can be very effective for manipulation the magnetic properties of amorphous ferromagnetic glass-coated microwires. Low coercivity and high giant magnetoimpedance (GMI) effect have been observed in as-prepared Co-rich microwires. After annealing of Co-rich microwires we can observe transformation of inclined hysteresis loops into rectangular and coexistence of fast magnetization switching and GMI effect in the same sample. We demonstrate that the switching field value of microwires can be tailored by annealing in the range from 4 to 200 A/m.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 694-697
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pressure on Magnetic Properties of Hexacyanochromates
Autorzy:
Mitróvá, Z.
Maťaš, S.
Mihalik, M.
Zentková, M.
Arnold, Z.
Kamarád, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813813.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.50.Ee
75.50.Gg
75.50.Xx
Opis:
We present the study of pressure effect on magnetic properties of $TM^{2+}_3[Cr^{III}(CN)_6]_2 \cdot nH_2O$ ferrimagnets and ferromagnets (TM = Cr and Co) under pressures up to 0.9 GPa. Applied pressure strengthens super-exchange interaction in $Cr^{2+}$-prussian blue analogues with dominant antiferromagnetic interaction $J_{AF}$ leading to increase in the Curie temperature $T_C$ (ΔT_c/Δp = 29.0 K/GPa) and reduces $T_C$ of $Co^{2+}$-prussian blue analogues with dominant ferromagnetic interaction $J_F$ (Δ$T_c$/Δp = -1.8 K/GPa). The rise of $J_{AF}$ interaction is attributed to the enhanced value of the single electron overlapping integral S. On the other hand, the applied pressure slightly affects bonding angles between magnetic ions mediated by the cyano-bridge and reduces the strength of magnetic coupling. Changes of the magnetization curve with pressure can be attributed to changes of magnetic anisotropy. The reduction of magnetization with pressure observed on $Cr^{2+}$-prussian blue analogues can be explained by pressure induced transition from $Cr^{2+}$ high spin state to $Cr^{2+}$ low spin state. All pressure induced changes are reversible.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 469-472
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pressure on Magnetic Properties of $TM_3[Cr(CN)_6]_2 \cdot nH_2O$ Nanoparticles
Autorzy:
Zentko, A.
Zentková, M.
Kavečanský, V.
Mihalik, M.
Mitróová, Z.
Arnold, Z.
Kamarád, J.
Cieslar, M.
Zeleňák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1813843.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.50.Ee
75.50.Gg
75.50.Xx
Opis:
Effect of pressure on magnetic properties of magnetic nanoparticles, based on Prussian blue analogues, were studied in pressures up to 1.2 GPa. The $Mn_3[Cr(CN)_6]_2 \cdot nH_2O$ and $Ni_3[Cr(CN)_6]_2 \cdot nH_2O$ nanoparticles were prepared by reverse micelle technique. Transmission electron microscopy images show nanoparticles with average diameter of about 3.5 nm embedded in an organic matrix. The characteristic X-ray peaks of nanoparticles are more diffused and broader. Systems of nanoparticles behave as systems of interacting magnetic particles. The Curie temperature $T_C$ is reduced from $T_C$ = 56 K for Ni-Prussian blue analogues to $T_C$ = 21 K for Ni-nanoparticles system and from $T_C$ = 65 K for Mn-Prussian blue analogues to $T_C$ = 38 K for Mn-nanoparticles system. One can explain this reduction of the Curie temperature and of the saturated magnetization $μ_s$ by dispersion of nanoparticles in an organic matrix i.e. by a dilution effect. Applied pressure leads to a remarkable increase in $T_C$ for system of Mn-nanoparticles (Δ$T_C$/Δp = +13 K/GPa) and to only slight decrease in $T_C$ for system of Ni-nanoparticles (Δ$T_C$/Δp = -3 K/GPa). The pressure effect follows behavior of the mother Prussian blue analogues under pressure. The increase in saturated magnetization, attributed to compression of the organic matrix, is very small.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 489-493
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Nano-Crystalline Barium Ferrite Synthesized by Different Synthesis Route
Autorzy:
Ovalioglu, H.
Sozeri, H.
Kabaer, M.
Kucuk, I.
Powiązania:
https://bibliotekanauki.pl/articles/1535266.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Ss
75.50.Ww
61.72.U-
Opis:
We have synthesized $Ba_{1-x}La_{x}Fe_{12}O_{19}$ (0 ≤ x ≤ 0.4) and $BaFe_{12-y}Nd_{y}O_{19}$ (0 ≤ y ≤ 4) samples in ammonium nitrate melt and nitric acid. The effects of La and Nd doping on the microstructure and magnetic properties of $BaFe_{12}O_{19}$ were investigated. The highest coercive field was obtained for the sample having La content, x = 0.3.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1020-1021
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocrystalline ZnO Doped with Fe$\text{}_{2}$O$\text{}_{3}$ - Magnetic and Structural Properties
Autorzy:
Kuryliszyn-Kudelska, I.
Hadžić, B.
Sibera, D.
Kilanski, L.
Romčević, N.
Romčević, M.
Narkiewicz, U.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/2048113.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
81.05.Dz
75.50.Lk
75.50.Vv
Opis:
We have studied the magnetic properties of ZnO nanocrystals doped with Fe$\text{}_{2}$O$\text{}_{3}$ in the magnetic dopant range from 5 to 70 wt%. The nanocrystals were synthesized by wet chemical method. The detailed structural characterization was performed by means of X-ray diffraction and micro-Raman spectroscopy measurements. The results of systematic measurements of magnetic AC susceptibility as a function of temperature and frequency are presented. We observed different types of magnetic behavior. For ZnO samples doped with low content of Fe$\text{}_{2}$O$\text{}_{3}$, the results of low-field AC susceptibility are satisfactorily explained by superparamagnetic model including inter-particle interactions. With the increase of magnetic Fe$\text{}_{2}$O$\text{}_{3}$ content, the spin-glass-like behavior is observed.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 689-691
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermomagnetic Properties and First-Order Reversal Curve Analysis of Annealed Fe-Co-Si-B-Mo-P Alloy
Autorzy:
Hasiak, M.
Miglierini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030239.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
75.60.-d
75.50.Tt
Opis:
The paper presents thermomagnetic features and characterization of magnetic interactions in the Fe₅₁Co₁₂Si₁₆B₈Mo₅P₈ metallic glass after annealing at 798 K for 1 h. The first-order reversal curve analysis was used to investigate hysteresis curves which provide a more precise estimation of the strength of interactions. The presence of magnetically distinct regions was revealed.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1222-1224
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of antisymmetric anisotropy on magnetisation of ultra-hard nanocrystalline alloys
Autorzy:
Ziółkowski, G.
Chrobak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1075870.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ww
75.30.Gw
75.50.Tt
Opis:
This paper describes an application of two-level Stoner-Wohlfarth model including antisymmetric anisotropy and two-level energetic model for simulations of magnetization processes in nanocrystalline, ultra-hard magnetic alloys. The simulation results have been compared with the experimental data obtained for the (Fe₈₀Nb₆B₁₄)_{0.88}Tb_{0.12} alloy. Moreover, the correctness of the proposed model was confirmed by the quantitative agreement with the direct Monte Carlo simulations of similar magnetic systems.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1137-1140
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Mn-Doped Amorphous $SiO_2$ Matrix
Autorzy:
Milivojević, D.
Babić-Stojić, B.
Jokanović, V.
Jagličić, Z.
Makovec, D.
Powiązania:
https://bibliotekanauki.pl/articles/1503690.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Lk
75.47.Lx
75.50.Tt
Opis:
Samples of Mn-doped amorphous $SiO_2$ matrix with manganese concentration 0.7 and 3 at.% have been prepared by a sol-gel method. Transmission electron microscopy analysis has shown that the samples contain agglomerates of amorphous silica particles 10 - 20 nm in size. Two types of Mn-rich particles are dispersed in silica matrix, smaller nanoparticles with dimensions between 3 and 10 nm, and larger crystalline areas consisting of aggregates of the smaller nanoparticles. High-temperature magnetic susceptibility reveals that dominant magnetic phase at higher temperatures is $λ-MnO_2$. At temperatures below $T_{C}$=43 K strong ferrimagnetism originating from the minor $Mn_3O_4$ phase masks the relatively weak magnetism of $λ-MnO_2$. Magnetic field dependence of the maximum in the zero-field-cooled magnetization for both the samples in the vicinity of 40 K, and a frequency shift of the real component of the AC magnetic susceptibility in the sample with 3 at.% Mn suggest that the magnetic moments of the smaller $Mn_3O_4$ nanoparticles with dimensions below 10 nm are subject to thermally activated blocking process just below the Curie temperature $T_{C}$. The low-temperature maximum in the zero-field-cooled magnetization observed for both the samples below 10 K indicates possible spin glass freezing of the magnetic moments in the geometrically frustrated Mn sublattice of the $λ-MnO_2$ crystal structure.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 316-321
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small Antiferromagnetic Spin Systems: Just beyond the Rotational Band Model
Autorzy:
Florek, W.
Kaliszan, L.
Powiązania:
https://bibliotekanauki.pl/articles/1385535.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
75.50.Ee
75.50.Xx
Opis:
Two systems of spins s=1/2 with the Heisenberg interactions are investigated: (i) an equilateral trapezoid and (ii) a regular hexagon. Both cases are compared with the corresponding sublattice Hamiltonians to determine splitting and mixing of energy levels with a given total spin of sublattices. It is shown that small modifications of the Hamiltonian parameters may significantly change (magnetic) properties of the eigenstates, especially probability of finding system in a state with determined value of the sublattice total spin.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 330-332
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:
Spin Crossover in Cu$\text{}_{x}$Co$\text{}_{y}$Cr$\text{}_{z}$Se$\text{}_{4}$ Semiconductors
Autorzy:
Maciążek, E.
Groń, T.
Pacyna, A. W.
Mydlarz, T.
Zawisza, B.
Krok-Kowalski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2048134.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Wx
75.50.Dd
75.50.Ee
Opis:
Magnetization and magnetic susceptibility measured in the zero-field-cooled mode were used to study the spin crossover transition in polycrystalline Cu$\text{}_{x}$Co$\text{}_{y}$Cr$\text{}_{z}$Se$\text{}_{4}$ compounds. With increasing Co content a transition from ferromagnetic order via ferrimagnetic one to antiferromagnetic-like behaviour was observed. This transition is accompanied with a lowering symmetry from cubic to monoclinic and for the latter the spin crossover phenomenon occurs. These results are considered in a framework of the ligand-field split and the spin-orbit coupling.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 711-713
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:
The Influence of Annealing Temperature on Magnetic Properties of Vitrovac 6030
Autorzy:
Lachowicz, H. K.
Popławski, F.
Żuberek, R.
Kulik, T.
Ślawska-Waniewska, A.
Kuźmiński, M.
Yu, S. C.
Dynowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2011100.pdf
Data publikacji:
1999-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Cc
75.50.Kj
75.60.Ch
Opis:
Co-Fe-Mo-Mn-Si-B metallic glass ribbon (Vitrovac 6030) was subjected to the isothermal annealing at temperatures in the range 523-873 K so as to produce a series of samples with gradually coarser microstructure. For this series of samples a giant increase in the coercivity, exceeding three orders of magnitude, is observed. This increase is interpreted in terms of the strengthening of the pinning effect of the nanocrystalline structure on the moving domain walls. It is shown that the anisotropy of the created crystallites is mainly responsible for the increase in the pinning force since the effective anisotropy seen by the wall becomes larger and larger with the gradual increase in the density and size of the grown particles.
Źródło:
Acta Physica Polonica A; 1999, 96, 3-4; 483-494
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Field-Induced Slow Magnetic Relaxation in Mn₉W₆ Cluster-Based Compound
Autorzy:
Konieczny, P.
Pełka, R.
Chorazy, S.
Podgajny, R.
Sieklucka, B.
Wasiutyński, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032251.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
75.40.Cx
75.50.Gg
Opis:
Magnetic measurements of a three-dimensional (3D) molecular magnet built of Mn₉[W(CN)₈]₆ clusters have been carried out to study its static and dynamic properties. Measurements of ac susceptibility in the presence of static magnetic field revealed slow magnetic relaxations. It was found that for the 120 Hz wave frequency the optimal static field which maximizes the imaginary component of the ac susceptibility is about 500 Oe.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 884-886
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly Degenerated Ground States in Some Rings Modeled by the Ising Spins with Competing Interactions
Autorzy:
Florek, W.
Antkowiak, M.
Kamieniarz, G.
Jaśniewicz-Pacer, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030746.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
75.50.Ee
75.50.Xx
Opis:
We discuss three Ising ring systems with competing interactions which are analogs of quantum systems and we show that they exhibit similar properties. In particular, the archetypal system of three antiferromagnetically coupled spins s has two magnetically degenerated ground states with |M|=s, when 0
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 411-413
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Open Source Implementation of Different Variants of Jiles-Atherton Model of Magnetic Hysteresis Loops
Autorzy:
Szewczyk, R.
Cheng, P.
Powiązania:
https://bibliotekanauki.pl/articles/1030747.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
75.50.Gg
75.60.Ej
Opis:
Jiles-Atherton model is one of the most advanced and most popular models of magnetic hysteresis loop. However, this model is considering different physical phenomena and computational issues. As a result, cross-validation of the results of modelling performed by different authors became difficult. For this reason, the open-source MATLAB/OCTAVE based implementation of Jiles-Atherton model was developed. Proposed implementation covers isotropic model of magnetic hysteresis loops as well as uniaxial and grain oriented electrical steel anisotropy. Moreover, the corrections proposed by Venkataraman together with different approaches to derivative of the anhysteretic magnetization are considered. Developed library is freely available together with the examples of magnetic hysteresis loops. As a result, it can be the base for further development of Jiles-Atherton model for better understanding of magnetization process as well as modelling the inductive components.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 654-656
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical properties study of the CeOsGa₄ compound
Autorzy:
Sondezi, B.
Strydom, A.
Powiązania:
https://bibliotekanauki.pl/articles/1047645.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.50.Cc
75.40.-s
Opis:
A polycrystalline sample of CeOsGa₄ was prepared by arc-melting stoichiometric quantities of high purity elements of 4N and greater, in an arc furnace. The data was confirmed to crystallize in an orthorhombic structure, with a space group Pmma (Number 51). Measurements of the magnetic susceptibility showed a distinct anomaly around T_{o} = 3.8 K, while the high temperature data (above 100 K) obeys Curie-Weiss law. The calculated effective moment of 2.44 μ_{B}, was obtained, which was a bit less than the theoretical moment for a Ce³⁺ ion of 2.54 μ_{B}. Magnetization data at T=2 K depicts that CeOsGa₄ does not saturate up to applied magnetic field of 7 T, while the data measured at 9 K indicates that the compound is purely paramagnetic at that temperature. The low temperature specific heat data is characterized by an anomaly at T_{o} = 3.8 K confirming the χ(T) data. Electrical resistivity shows a metallic behaviour at high temperatures with a deviation at low temperatures, signalling the cooperative behaviour which results to ordering. In this work we present the initial studies of the physical properties measurements performed on this compound.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 398-400
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of magnetic properties during annealing of Hf₂Co₁₁B amorphous alloy
Autorzy:
Musiał, A.
Śniadecki, Z.
Idzikowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1050942.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ww
75.60.Nt
75.50.Kj
Opis:
Influence of heat treatment on magnetic properties of amorphous Hf₂Co₁₁B alloy was investigated. Hard magnetic phase, characterized by high magnetic anisotropy, appears during crystallization. The highest coercive field equal to 1.86 kOe, was obtained for sample annealed in third crystallization stage. Longer heat treatment at T_{a} = 650°C leads to decrease in coercive field, which can be the result of excess of the HfCo₃B₂ phase volume fraction and additionally eutectoid transformation of hard magnetic phase into soft magnetic Co₂₃B₆ and fcc-Co. Decrease of volume fraction of hard phase is confirmed by the remanence ratio m_{r}. Value of m_{r}, for T_{a} = 650°C, is decreasing with annealing time from 0.4 to 0.27 for 30 min and 120 min, respectively. The magnetocrystalline anisotropy constant K₁ increases from 2.23 Merg/cm³ for the amorphous ribbon to 15.84 Merg/cm³ for the sample annealed at 650°C for 30 min.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 786-788
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Giant Magnetoimpedance in Amorphous and Nanocrystalline Microwires
Autorzy:
Talaat, A.
Zhukova, V.
Ipatov, M.
Blanco, J.
Churyukanova, M.
Kaloshkin, S.
Kostitcyna, E.
Shuvaeva, E.
Gonzalez-Legarreta, L.
Hernando, B.
Zhukov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1200823.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
75.30.Gw
75.50.-y
Opis:
We studied magnetic properties and GMI effect of Finemet-type FeCuNbSiB microwires. We observed that GMI effect and magnetic softness of microwires produced by the Taylor-Ulitovski technique, can be tailored by either controlling magnetoelastic anisotropy of as-prepared FeCuNbSiB microwires or controlling their structure by heat treatment or changing the fabrication conditions. GMI effect has been observed in as-prepared Fe-rich microwires with nanocrystalline structure.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 146-147
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Spin-Low Spin Transitions in $Cu_{0.2}Co_{0.76}Cr_{1.83}Se_4$ Semiconductor
Autorzy:
Maciążek, E.
Groń, T.
Pacyna, A.
Mydlarz, T.
Krok-Kowalski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1489908.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Wx
75.50.Dd
75.50.Ee
Opis:
Magnetization, ac and dc magnetic susceptibility measured in the zero-field-cooled mode were used to study the high spin-low spin transitions in polycrystalline $Cu_{0.2}Co_{0.76}Cr_{1.83}Se_4$ semiconductor. The real part component of fundamental susceptibility $χ_1^\prime$ (T) and its second $(χ_2)$ and third $(χ_3)$ harmonics revealed two spectacular peaks at 128 K and at 147 K, confirming the appearance of the spin-crossover phenomenon.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 687-689
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Thermal Treatment on Frequency Dependence of the Switching Field in Amorphous and Nanocrystalline FeNiMoB Microwires
Autorzy:
Komova, E.
Varga, R.
Vazquez, M.
Powiązania:
https://bibliotekanauki.pl/articles/1507122.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
75.60.Ej
75.50.Tt
Opis:
Amorphous and nanocrystalline ferromagnetic glass-coated microwires show excellent magnetic properties that make them very suitable to be employed as sensing elements in devices for technical applications. New $Fe_{40}Ni_{38}Mo_4B_{18}$ alloy composition can be appropriate to prepare soft magnetic nanocrystalline microwires which exhibit magnetic bistability even in the nanocrystalline state. Stability of magnetic properties after different thermal treatments ($T_{a}$ = 250-425°C) and after nanocrystallization was confirmed by the switching field $H_{sw}$ measurements. The frequency dependence of the switching field was investigated. Two contributions to the domain wall switching mechanism were recognized: magnetoelastic one coming from the magnetoelastic interaction of the magnetic moments with the stresses and relaxation one coming from the structural relaxation of local defects at atomic scale. But, the relative role of both contributions has been shown to vary strongly in different stage of devitrification.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 768-769
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the Magnetic Characteristics of Isotropic and Anisotropic Materials for Sensor Applications
Autorzy:
Szewczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/1813527.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ej
75.50.Gg
75.50.Kj
Opis:
The following paper presents the results of modelling of the magnetic characteristics of isotropic (Ni-Zn ferrite) and anisotropic material ($Fe_{40}Ni_{38}Mo_4B_{18}$ amorphous alloy in as quenched state), both useful for sensor applications. For the modelling an extended Jiles-Atherton model was used. Extension of the model connects model's parameter k, describing average energy required to break pinning site, with magnetic state of the material. Such extension of the model is reasonable from the physical point of view. Good agreement between experimental data and modelling confirms that the extended Jiles-Atherton model creates the possibility of modelling of magnetic characteristics of both isotropic and anisotropic magnetic cores.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 67-70
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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