Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 18

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Publication available in full text mode
Content available

Distance Dependence of the Mn-Mn Exchange Interaction in IV-VI Semimagnetic Semiconductors

100%
Łusakowski A., Górska M.
|
EN
In the present paper we calculate the exchange interaction between two manganese ions in IV-VI semiconductors with the rocksalt structure. The method of calculations is based on the fourth order perturbation theory with respect to hybridization between band states and localized d orbitals of Mn ions. This hybridization is described by three Harrison integrals: V_{pdσ},V_{pdπ}, and V_{sdσ}. The band states of IV-VI semiconductor are obtained from the semiempirical tight binding model built from s and p orbitals of cations and anions. The resulting exchange term in the Hamiltonian is of the form -Σ_{i,j=xyz}J_{ ij}Ŝ^1_iŜ^2_j, however nondiagonal terms of the exchange integral tensor J_{i≠j} are very small. The dependence of J_{ij} on the Mn-Mn distance is non-monotonic. We also discuss the influence of the local crystal deformations on the exchange integral.
2
Content available remote

Magnetic Susceptibility of Pb_{1-x-y}Sn_{y}Mn_{x}Se

81%
Górska M., Anderson J. R., Kowalczyk L.
Acta Physica Polonica A
|
1991
|
vol. 79
|
issue 2-3
385-387
EN
Magnetic susceptibility has been measured in Pb_{1-x-y}Sn_{y}Mn_{x}Se with x values up to 0.02 and y values up to 0.05. The measurements were carried out using a SQUID system over a temperature range from 5 to 250 K. The susceptibility followed the Curie-Weiss relation with a small paramagnetic Curie temperature that indicated a weak antiferromagnetic exchange interaction between Mn ions. We analyzed the results together with our previously published data on high-field magnetization in this material. A reasonable agreement of the exchange parameters obtained from the low-field susceptibility and high-field magnetization data was obtained.
3
Content available remote

Magnetization and Susceptibility of Sn_{1-x}Gd_{x}Te

81%
Górska M., Górska J., Green S., Golacki Z.
Acta Physica Polonica A
|
1991
|
vol. 80
|
issue 3
377-380
EN
The magnetization and magnetic susceptibility of Bridgman-grown Sn_{1-x}Gd_{x}Te with values of x up to 0.09 have been measured over a temperature range from 2 to 300 K and in magnetic fields up to 5.5 T. The magnetic susceptibility data followed the Curie-Weiss relation with a small Curie temperature that indicated a weak antiferromagnetic coupling among Gd ions. The magnetic field dependence of the magnetization was fitted to a modified Brillouin function with parameter values that agreed fairly well with those from Curie-Weiss plots. The value of the exchange parameter was larger than in Pb_{1-x}Gd_{x}Te. The samples were p-type with carrier concentrations up to 1.3 x 10^{21} cm^{-3}. The ferromagnetic or spin-glass phase due to the RKKY interaction was not observed.
4
Content available remote

Magnetic Susceptibility of Sn_{1-x}Au_{x}Te

81%
Górska M., Anderson J., Peng J., Gołacki Z.
Acta Physica Polonica A
|
1993
|
vol. 84
|
issue 4
665-668
EN
The magnetic susceptibility of Bridgman-grown Sn_{1-x}Eu_{x}Te with nominal values of x up to 0.095 was measured over a temperature range from 2 to 385 K. The samples were p-type with hole concentrations up to 1.5 × 10^{21} cm^{-3}. The susceptibility data above 50 K followed the Curie-Weiss relation with a small Curie temperature. At about 10 K a small cusp in susceptibility was observed in samples with the higher range of x values. The data indicate a presence of both antiferromagnetic and ferromagnetic exchange interactions, with some paramagnetic contributions from charged defects. There is also evidence of Eu going into the lattice both as Eu^{2+} and Eu^{3+} ions.
5
Content available remote

Anomalous Behavior of the Hall Effect in III-V Heterostructures

71%
Dziuba Z., Górska M., Marczewski J., Przesławski T., Regiński K.
Acta Physica Polonica A
|
2000
|
vol. 97
|
issue 2
331-336
EN
The Hall effect and magnetoresistance were measured in the InAs/GaAs heterostructure at temperatures from 300 K down to 3 K, in a magnetic field range from 0.01 to 1.5 T. The anomalous magnetic field dependence of the Hall coefficient in the InAs/GaAs heterostructure in magnetic fields below 0.1 T was explained as due to an extraordinary Hall effect caused by skew scattering on dislocations.
6
Content available remote

Magnetization and Susceptibility of Cd_{1-x}Co_{x}Se

71%
Górska M., Anderson J., Green S., Kido G., Giriat W.
Acta Physica Polonica A
|
1992
|
vol. 82
|
issue 5
753-756
EN
The magnetization and magnetic susceptibility of Bridgman-grown Cd_{1-x}Co_{x}Se with values of x up to 0.04 have been measured over a temperature range from 2 to 390 K and in magnetic fields up to 23 T. A pair-exchange value J/k_{B} of about -3 K was obtained from the magnetic field dependence of the magnetization. This exchange is probably due to the next-nearest-neighbor interaction. The high-temperature susceptibility data indicated a presence of the Curie-Weiss like paramagnetism and the temperature independent Van Vleck type paramagnetism.
7
Publication available in full text mode
Content available

Magnetic Specific Heat of Pb_{1-x}Eu_xTe

62%
Górska M., Łusakowski A., Jędrzejczak A., Gołacki Z., Anderson J., Balci H.
Acta Physica Polonica A
|
2004
|
vol. 105
|
issue 6
631-636
EN
The temperature dependence of the magnetic specific heat was studied experimentally and theoretically in the semimagnetic semiconductor Pb_{1-x}Eu_xTe for x=0.027 and x=0.073, over the temperature range from 0.5 K to 15 K, in magnetic fields up to 2 T. In zero magnetic field at about 2 K there was a broad maximum in the magnetic specific heat, which was much higher than that predicted by the model of superexchange interaction between nearest neighbors; the maximum values increased with magnetic field. The experimental data were analyzed in the framework of a model which takes into account the spin splitting of the ground state of a single Eu2+ ion in the presence of local lattice distortions in the Pb_{1-x}Eu_xTe mixed crystal. The model describes well the experimental data, especially for lower x-values, where the contribution from singlets dominates.
8
Content available remote

High Field Magnetization of Sn_{1-x}Gd_{x}Te

62%
Górska M., Anderson J., Wolters C., Łusakowski A., Story T., Gołacki Z.
Acta Physica Polonica A
|
1998
|
vol. 94
|
issue 2
347-350
EN
The magnetization of p-type Sn_{1-x}Gd_{x}Te with x up to 0.045 and the hole concentration, p, varying from 2.7 to 8.3×10^{20} cm^{-3} has been measured in magnetic fields up to 27 T, at the temperatures 4.2 and 1.3 K. The data were fitted to a magnetization equation with single-ion and pair terms. From comparison of the exchange parameters determined from the high-field magnetization with those previously obtained from the high-temperature magnetic susceptibility it was found that in samples with p>5×10^{20} cm^{-3} the exchange was of a short-range type, while in samples with a lower carrier concentration the long-range exchange mechanism was observed.
9
Content available remote

Magnetic Properties of Sn_{1-x}Cr_xTe Diluted Magnetic Semiconductors

52%
Kilanski L., Podgórni A., Górska M., Dobrowolski W., Slynko V., Slynko E., Reszka A., Kowalski B.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 5
881-884
EN
We present the studies of Sn_{1-x}Cr_xTe semimagnetic semiconductors with chemical composition x ranging from 0.004 to 0.012. The structural characterization indicates that even at low average Cr-content x ≤q 0.012, the aggregation into micrometer size clusters appears in our samples. The magnetic properties are affected by the presence of clusters. In all our samples we observe the transition into the ordered state at temperatures between 130 and 140 K. The analysis of both static and dynamic magnetic susceptibility data indicates that the spin-glass-like state is observed in our samples. The addition of Cr to the alloy seems to shift the spin-glass-like transition from 130 K for x = 0.004 to 140 K for x = 0.012.
10
Content available remote

The Role of Frustration in Magnetism of Ge_{1-x}Cr_{x}Te Semimagnetic Semiconductor

52%
Kilanski L., Górska M., Dobrowolski W., Arciszewska M., Domukhovski V., Anderson J., Butch N., Podgórni A., Slynko V., Slynko E.
Acta Physica Polonica A
|
2011
|
vol. 119
|
issue 5
654-656
EN
We present preliminary studies of magnetic properties of Ge_{1-x}Cr_{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.
11
Content available remote

Transport and Magnetic Study of Gd Ions in Pb_{1-y}Sn_{y}Te

52%
Story T., Arciszewska M., Łazarczyk P., Łusakowski A., Górska M., Dobrowolski W., Witkowska B., Grodzicka E., Gałązka R.
Acta Physica Polonica A
|
1997
|
vol. 92
|
issue 5
997-1000
EN
Electric conductivity, Hall effect and magnetic susceptibility of Pb_{1-x-y} Sn_{y}Gd_{x}Te mixed crystals with 0.13 ≤ y ≤ 0.93 and 0.001 ≤ x ≤ 0.04 were experimentally studied over the temperature range 4K ≤ T ≤ 300 K. The incorporation of Gd ions into the Pb_{1-y}Sn_{y}Te matrix results in semi-metallic n-type conductivity of the crystals with y < 0.6. For crystals with y > 0.6 one observes only semi-metallic p-type conductivity. We present a model explaining these results in terms of the Sn composition dependence of the location of Gd^{2+/3+} level with respect to the band edges of PbSnGdTe.
12
Content available remote

Magnetic Properties of Sn_{1-x}Gd_{x}Te (0.002 ≤ x ≤ 0.09)

52%
Story T., Arciszewska M., Dobrowolski W., Gołacki Z., Górska M., Grodzicka E., Łusakowski A., Dynowska E., Witkowska B.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 5
935-938
EN
Magnetic, transport and structural properties of bulk crystals of Sn_{1-x}Gd_{x}Te with Gd content 0.002 < x < 0.09 and varying carrier concentrations obtained by an isothermal annealing were studied in the temperature range T = 1.5 - 80 K. We found the effect of resonant increase in antiferromagnetic spin-spin exchange interactions in the crystals with 0.025 ≤ x ≤ 0.05. No effect was found in crystals either with higher (x > 0.05) or with lower (x < 0.025) Gd concentration. The observed Gd composition dependence of the magnetic and transport properties of SnGdTe can be explained in a proposed model relating these experimental properties to the Gd composition induced shift of the position of Gd^{3+/2+} level with respect to the top of the valence band of SnGdTe.
13
Content available remote

The Role of Frustration in Magnetism of Ge_{1-x}Cr_{x}Te Semimagnetic Semiconductor Acta Physica Polonica A 119, 654 (2011), ERRATUM

52%
Kilanski L., Górska M., Dobrowolski W., Arciszewska M., Domukhovski V., Anderson J., Butch N., Podgórni A., Slynko V., Slynko E.
Acta Physica Polonica A
|
2011
|
vol. 119
|
issue 6
904
14
Content available remote

Anomalous Hall Effect in Ge_{1-x-y}Pb_{x}Mn_{y}Te Composite System

52%
Podgórni A., Kilanski L., Dobrowolski W., Górska M., Domukhovski V., Brodowska B., Reszka A., Kowalski B., Slynko V., Slynko E.
|
|
vol. 126
|
issue 5
1180-1183
EN
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.
15
Content available remote

Spinodal Decomposition of Magnetic Ions in Eu-Codoped Ge_{1-x}Cr_{x}Te

43%
Podgórni A., Kilanski L., Dobrowolski W., Górska M., Reszka A., Domukhovski V., Kowalski B., Brodowska B., Anderson J., Butch N., Slynko V., Slynko E.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 6
1012-1015
EN
We present the experimental evidence for the presence of spinodal decomposition of the magnetic ions in the Ge_{1-x-y}Cr_{x}Eu_{y}Te samples with chemical composition varying in the range of 0.015 ≤ x ≤ 0.057 and 0.003 ≤ y ≤ 0.042. The ferromagnetic transition at temperatures 50 ≤ T ≤ 57 K was observed, independent of the chemical composition. The long-range carrier mediated itinerant magnetic interactions seem to be responsible for the observed ferromagnetic order. The magnetic irreversibility with coercive field H_C = 5 - 63 mT and the saturation magnetization M_S ≈ 2 - 6 emu/g are found to strongly depend on the chemical composition of the alloy.
16
Publication available in full text mode
Content available

High power QW SCH InGaAs/GaAs lasers for 980-nm band

43%
Bugajski M., Mroziewicz B., Regiński K., Muszalski J., Kosiel K., Zbroszczyk M., Ochalski T., Piwoński T., Wawer D., Szerling A., Kowalczyk E., Wrzesińska H., Górska M.
|
2005
|
vol. 53
|
issue 2
17
Content available remote

Magnetic Order and Magnetic Inhomogeneities in SnCrTe-PbCrTe Solid Solutions

43%
Kilanski L., Szymański M., Brodowska B., Górska M., Szymczak R., Podgórni A., Avdonin A., Reszka A., Kowalski B., Domukhovski V., Arciszewska M., Dobrowolski W., Slynko V., Slynko E.
|
|
vol. 126
|
issue 5
1203-1206
EN
We present the studies of structural, electrical and magnetic properties of bulk Sn_{1-x-y}Pb_xCr_yTe mixed crystals with chemical composition 0.18 ≤ x ≤ 0.35 and 0.007 ≤ y ≤ 0.071. The magnetometric studies indicate that for the high Cr-content, y=0.071, the alloy shows ferromagnetic alignment with the Curie temperature, T_{C}, around 265 K. The Cr_5Te_8 clusters are responsible for the ferromagnetic order. At low Cr content, y ≈ 0.01, a peak in the ac magnetic susceptibility identified as the cluster-glass-like transition is observed at a temperature about 130 K. The cluster-glass-like transition is likely due to the presence of Cr_2Te_3 clusters in the samples with y ≈ 0.01. The transport characterization of the samples indicated strong metallic p-type conductivity with relatively high carrier concentration, n > 10^{20} cm^{-3}, and carrier mobility, μ > 150 cm^2/(V s).
18
Content available remote

Magnetic Properties of Epitaxial (Ge,Mn)Te Thin Films with Varying Crystal Stoichiometry

43%
Knoff W., Domukhovski V., Dybko K., Dziawa P., Górska M., Jakieła R., Łusakowska E., Taliashvili B., Story T., Reszka A., Anderson J., Rotundu C.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 5
1159-1165
EN
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).
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.