Wyniki wyszukiwania - Biblioteka Nauki

1

Magnetic Susceptibility of PbSnMnTe in the Transition Region between Ferromagnetic and Spin Glass Phase

100%

Story T. , Gałązka R. , Eggenkamp P. , Swagten H. , de Jonge W.

Acta Physica Polonica A

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1992

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tom 82

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nr 4

630-633

EN

The ac magnetic susceptibility (χ) was measured in the temperature range T = (1.5÷50) K for Pb_{1-x-y}Sn_{y}Mn_{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^{20} cm^{-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.

2

Magnetic Anisotropy in Pb_{1-x-y}Sn_{y}Mn_{x}Te Studied by Ferromagnetic Resonance

100%

Eggenkamp P. , Story T. , Swüste C. , Swagten H. , de Jonge W.

Acta Physica Polonica A

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1993

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tom 84

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nr 4

641-644

EN

We will report on the anisotropy in (Pb)SnMnTe, studied by ferromagnetic resonance. We have found a cubic anisotropy with a = 73 × 10^{-4} cm^{-1} for Sn_{1-x}Mn_{x}Te and a = 200 × 10^{-4} cm^{-1} for Pb_{0.28-x}Sn_{0.72}Mn_{x}Te. We will indicate some possible explanations for this anomalously large anisotropy.

3

Specific Heat of Cr-Based Semimagnetic Semiconductors

100%

Twardowski A. , Eggenkamp P. , Mac W. , Swagten H. , Demianiuk M.

Acta Physica Polonica A

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1993

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tom 84

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nr 3

563-565

EN

Specific heat of ZnCrSe and ZnCrS was measured for 1.5 < T < 10 K and B < 3 T. The data were interpreted using "crystal field model" taking into account tetrahedral crystal field, tetragonal Jahn-Teller distortion and spin-orbit interaction.

4

Magnetic Anisotropy in Eus-pbs Multilayers

72%

Story T. , Swüste C. , Swagten H. , de Jonge W. , Stachow-Wójcik A. , Twardowski A. , Arciszewska M. , Dobrowolski W. , Gałązka R. , Sipatov A.

Acta Physica Polonica A

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2000

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tom 97

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nr 3

435-438

EN

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_{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_{V}+2K_{S}/d , with the surface term K_{S} larger for layers grown on BaF_{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.

5

Temperature Dependence of Antiferromagnetic Interlayer Exchange Coupling in EuS-PbS Multilayers

72%

Chernyshova M. , Kowalczyk L. , Baran M. , Szczerbakow A. , Story T. , Smits C. , Filip A. , Swagten H. , de Jonge W. , Sipatov A.

Acta Physica Polonica A

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2004

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tom 105

|

nr 6

599-605

EN

Antiferromagnetic interlayer exchange coupling in semiconductor EuS-PbS-EuS ferromagnetic trilayers grown on PbS (001) substrates with ultrathin (0.6-1.2 nm) nonmagnetic PbS spacers is studied by SQUID magnetometry and model calculations. Analysis of the experimentally observed magnetic field and temperature dependence of the magnetization of EuS-PbS structures reveals a rapid decrease in the interlayer coupling energy with increasing temperature indicating a temperature dependence of the microscopic coupling mechanism acting in these all-semiconductor ferromagnetic/nonmagnetic multilayers.

6

Resonant State of 4f^{14/13} Yb Ion in Pb_{1-x}Ge_{x}Te

72%

Grodzicka E. , Dobrowolski W. , Story T. , Slynko E. , Vygranenko Y. K. , Willekens M. , Swagten H. , de Jonge W.

Acta Physica Polonica A

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1996

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tom 90

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nr 4

801-804

EN

The study of transport and of magnetic properties of Pb_{1-x}Ge_{x}Te:Yb mixed crystals (0 ≤ x ≤ 0.04) is reported. It is shown that Yb forms a donor state resonant with the PbTe valence band. The donor state position may be tuned (shifted relative to the energy gap) by admixture of Ge. The properties of the Yb ion in the Pb_{1-x}Ge_{x}Te matrix makes the system unique from the point of view of magnetic properties. It is demonstrated that the change of the conductivity type from p to n induces transitions from the paramagnetic state to the diamagnetic one.

7

Magnetic and Structural Properties of EuS-PbS Multilayers Grown on n-PbS (100) Substrates

58%

Chernyshova M. , Łusakowska E. , Domukhovski V. , Grasza K. , Szczerbakow A. , Wrotek S. , Kowalczyk L. , Story T. , Smits C. , Swagten H. , De Jonge W. , Palosz W. , Sipatov A. , Volobuev V.

Acta Physica Polonica A

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2002

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tom 102

|

nr 4-5

609-615

EN

Magnetic properties of semiconductor EuS(t)-PbS(d)-EuS(t) ferromagnetic trilayers (t=30÷300Å and d=7.5÷70Å) grown on n-type monocrystalline PbS (100) substrate were studied by SQUID magnetometry and ferromagnetic resonance technique yielding, in particular, the dependence of the ferromagnetic Curie temperature on the thickness of the EuS layer. Structural parameters of layers were examined by X-ray powder diffraction analysis. A high structural quality of the substrate and the multilayer was verified by the measurements of the X-ray rocking curve width indicating the values of the order of 100 arcsec and by atomic force microscopy revealing the presence on the cleft PbS surface regions practically flat in the atomic scale over the area of 1×0.1μm^2.