Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Refine search results

Journals help

  1. 29 Acta Physica Polonica A

Years help

  1. 1 2018

  2. 1 2015

  3. 3 2014

  4. 1 2013

  5. 3 2012

More...
Authors help

  1. 7 Kossacki P.

  2. 4 Cibert J.

  3. 4 Dietl T.

  4. 4 Ferrand D.

  5. 4 Gaj J.

More...
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 29

Number of results on page
first rewind previous Page / 2 next fast forward last

Search results

Search:
in the keywords:  75.30.Hx
help Sort By:

help Limit search:
first rewind previous Page / 2 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.
Acta Physica Polonica A
|
2003
|
vol. 103
|
issue 6
659-664
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

Is the Magnetism of HgSe:Fe Clearly Understood?

100%
Dybko K., Łusakowski A., Kossut J., Arciszewska M., Linden P. J. E. M. v., Wittlin A., Perenboom J. A. A. J., Mycielski A.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 1
193-196
EN
The high magnetic field magnetization measurements of low composition Hg_{1-x}Fe_{x}Se (0.0002 < x < 0.003) at temperatures ranging from 1.6 K to 40 K and in magnetic fields up to 20 T are reported. The magnetization in a sample containing only Fe^{3+} ions (x = 0.0002) is described by the Brillouin function (j = 5/2). The magnetization in the sample codoped with Ga, containing only Fe^{2+} is well described in the model of isolated Fe^{2+} ions. The latter model takes into account the tetrahedral crystal field, the spin-orbit interaction and the Zeeman term. On the other hand, the magnetization of sample with both Fe^{3+} and Fe^{2+} present simultaneously (x = 0.003) is shown to be different from a simple additive superposition of the contributions due to Fe^{3+} and Fe^{2+} subsystems. The possible origin of this discrepancy is discussed.
3
Content available remote

RKKY-Reminiscent Interaction in Net Fractals

100%
Jaroszewicz R.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
329-331
EN
We define a specific class of fractals as "net fractals" and prove that in the logarithmic scale they are isomorphic with some bulk crystals. Furthermore, with the use of logarithmic coordinates, we prove that in the "net fractal" magnetic system the indirect exchange, by itinerant electrons can be presented in the form that is reminiscent of the Ruderman-Kittel-Kasuya-Yosida interaction characteristic of a system of fractional spectral dimension.
4
Content available remote

Magnetic Order and Magnetic Inhomogeneities in SnCrTe-PbCrTe Solid Solutions

80%
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.
Acta Physica Polonica A
|
2014
|
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).
5
Content available remote

Indirect Coupling Between Localized Magnetic Moments in Zero-Dimensional Graphene Nanostructures (Quantum Dots)

80%
Szałowski K.
Acta Physica Polonica A
|
2014
|
vol. 126
|
issue 1
236-237
EN
The indirect Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling between on-site magnetic impurities is studied for two kinds of graphene nanoflakes consisting of approximately 100 carbon atoms, posessing either zigzag or armchair edge. The tight-binding Hamiltonian with Hubbard term is used in non-perturbative calculations of coupling between the impurities, placed at the edge of the structure. In general, for zigzag-edged nanoflakes a pronounced coupling robust against charge doping is found, while for armchair-edged structures the interaction is weaker and much more sensitive to charge doping. Also the distance dependence of indirect exchange differs significantly for both edge forms.
6
Content available remote

Magnetic Properties of MeB_{50} (Me = 3d Atom) Compounds

80%
Panfilov A., Grechnev G., Filipov V., Lyashchenko A., Levchenko G.
Acta Physica Polonica A
|
2014
|
vol. 126
|
issue 1
400-401
EN
Temperature dependence of the static magnetic susceptibility for higher borides MeB_{50}, where Me = V, Cr, Mn, Fe, Co and Ni, was measured by Faraday method in the temperature range of 78-300 K. The value of effective magnetic moment of 3d-ions, resulted from the experiment, is compared with corresponding data of the ab initio calculations of the electronic structure and magnetic properties of these compounds based on the density functional theory.
7
Content available remote

A Monte Carlo Study of Critical Properties of Strongly Diluted Magnetic Semiconductor (Ga,Mn)As

80%
Tomczak P., Diep H., Jabłoński P., Puszkarski H.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 3
514-516
EN
Within a Monte Carlo technique we examine critical properties of diluted bulk magnetic semiconductor (Ga,Mn)As modeled by a strongly diluted ferromagnetic Heisenberg spin-5/2 system on a face centered cubic lattice. We assumed that 5% of Ga atoms is substituted by Mn atoms and the interaction between them is of the RKKY-type. The considered system is randomly quenched and a double average was performed: firstly, over the Boltzmann probability distribution and secondly - over 2048 configurations related to the quenched disorder. We estimated the critical temperature: T_{c}=97±6 K, which is in agreement with the experiment.
8
Publication available in full text mode
Content available

Ferromagnetism in II-VI Based Semiconductor Structures

80%
Cibert J., Ferrand D., Tatarenko S., Wasiela A., Kossacki P., Dietl T.
Acta Physica Polonica A
|
2001
|
vol. 100
|
issue 2
227-236
EN
The experimental results on carrier-induced ferromagnetic interaction in II-VI diluted magnetic semiconductors are shortly reviewed and analyzed in the light of the mean field approximation. We particularly take the point of view of the experimentalist to emphasize (i) points which are easily understood within this simple model (as the role of the detailed structure of the valence band) and hence should be incorporated into more sophisticated models, and (ii) points which are not taken into account in the mean field model (e.g., disorder effects) and hence call for more elaborate descriptions. We particularly discuss the case of a low carrier density, and show that the situation appears as experimentally very different in the highly disordered 3D layers and in the modulation doped 2D quantum wells.
9
Content available remote

On Theoretical Study of Magnetic Behavior of Diamond Doped with Transition Metals

80%
Hussain F., Ullah M., Ullah H., Rashid M., Imran M., Ahmad E.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 3
823-826
EN
We study the magnetic behavior of the diamond system. In this system diamond bulk is involved which is doped with different transition metals, namely Cu, Cd, Hg, and Zn. The VASP code is employed for all calculations which are based on density functional theory. The substitutional point defects is introduced in the diamond bulk and occupied by the transition metals. Results exhibit that all transition metals show ferromagnetism behavior and Cu is a good advocate of conductivity among all transition metals. The range of magnetic moments is 2.89, 1.99, 1.96, and 1.80 μ_{B} per Cu, Cd, Hg, and Zn atom in diamond bulk, respectively. Strong magnetic behavior points out that these materials could be used for spintronics.
10
Content available remote

Free Carrier Concentration Dependence of Gd-Gd Exchange Constant in SnTe:Gd

80%
Łusakowski A.
Acta Physica Polonica A
|
1995
|
vol. 88
|
issue 5
1018-1022
EN
In some samples of SnTe:Gd the measured paramagnetic Curie temperature strongly depends on the Fermi level position. The semi-quantitative theory which explains this effect is presented. The theory is based on Kasuya's model of exchange interaction between two 4f spins of rare earth ions. In this model the interaction between 4f electrons and the valence band goes via Gd atomic 5d orbitals which, contrary to the 4f orbitals are much more extended in space. The exchange integral and the paramagnetic Curie temperature dependence on the Fermi level position are calculated.
11
Content available remote

Free Carriers Heating at Mn^{2+} Magnetic Resonance in CdMnTe

80%
Godlewski M., Gałązka R., Tsimperidis I., Gregorkiewicz T., Ammerlaan C.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 1
177-180
EN
The results of optically detected magnetic and cyclotron resonance ex­periments performed on Cd_{1-x}Mn_{x}Te (x = 0.007) are presented. It is shown that the Mn^{2+} magnetic resonance results in heating of free holes, which can be observed via the effects of hot holes on the CdMnTe "edge" emission.
12
Content available remote

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

80%
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.
13
Content available remote

Diluted Magnetic Semimetals - Beyond Heisenberg Coupling

80%
Wilamowski Z., Story T., Jantsch W.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 1
189-192
EN
We analyse effects which cannot be explained assuming the isotropic Heisenberg form of sp-d or of the indirect d-sp-d (RKKY) coupling. Resonance line broadening, a line shift and an enhancement of the magnetic anisotropy in diluted magnetic semimetals are discussed.
14
Publication available in full text mode
Content available

Gd^{3+}-RE^{3+} Exchange Interactions in Rare-Earth Fluoride Crystals (RE = Ce, Nd, Yb)

80%
Paradowski M., Misiak L.
Acta Physica Polonica A
|
2004
|
vol. 105
|
issue 5
445-457
EN
The investigation of Gd^{3+}-doped LaF_3, La_{0.9}Ce_{0.1}F_3, CeF_3, La_{0.9}Nd_{0.1}F_3, LiYF_4, and LiY_{0.9}Yb_{0.1}F_4 single crystals at 4.2 K was carried out in order to study the Gd^{3+}-RE^{3+} exchange interactions (RE = Ce, Nd, Yb). The exchange interactions were estimated by the application of the molecular-field model at liquid-helium temperature, using the g shift from the isostructural diamagnetic hosts LaF_3 and LiYF_4 to the paramagnetic hosts. The lattice dynamics is studied by analysing spin-Hamiltonian parameters in the light of the superposition model and the rotational invariance theory for phonon-induced contributions to spin-Hamiltonian parameters. It is suggested from the rotational invariance mechanism for phonon-induced contributions to spin-Hamiltonian parameters that the rotational contributions influence the exchange interactions significantly. Further, the distortions caused by the La^{3+}/Ce^{3+}, La^{3+}/Nd^{3+}, and Y^{3+}/Yb^{3+} substitutions affect significantly the 4f^7 electron-phonon interactions, as well as the exchange interactions. The magnitude of the isotropic exchange interactions is larger for more symmetrical charge distribution of the 4f^7 shell.
15
Content available remote

Permanent Magnetism in Thiol Capped Nanoparticles Gold and ZnO

80%
Crespo P., García M., Fernández-Pinel E., de la Venta J., Merino J., Quesada A., Hernando A., Fernández A., Penadés S.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 1
515-520
EN
In spite of the diamagnetic behavior exhibited by bulk ZnO and Au, a ferromagnetic-like behavior is induced in nanoparticles of both systems by appropriate surface functionalization. By capping with thiol derivatized molecules, magnetic hysteresis is observed even at room temperature, whereas the magnetization has a very little temperature dependence. Capping induces an alteration of their electronic configuration that depends on the capping molecule, as evidenced by X-ray absorption spectroscopy, that strongly affects their magnetic properties.
16
Content available remote

Magnetooptical Properties of (Ga,Fe)N Layers

80%
Papierska J., Rousset J., Pacuski W., Kossacki P., Golnik A., Nawrocki M., Gaj J., Suffczyński J., Kowalik I., Stefanowicz W., Sawicki M., Dietl T., Navarro-Quezada A., Faina B., Li T., Bonanni A.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 5
921-923
EN
Magnetooptical properties of (Ga,Fe)N layers containing various concentrations of Fe-rich nanocrystals embedded in paramagnetic (Ga,Fe)N layers are reported. Previous studies of such samples demonstrated that magnetization consists of a paramagnetic contribution due to substitutional diluted Fe ions as well as of ferromagnetic and antiferromagnetic components originating from Fe-rich nanocrystals, whose relative abundance can be controlled by the growth conditions. The nanocrystals are found to broaden and to reduce the magnitude of the excitonic features. However, the ferromagnetic contribution, clearly seen in SQUID magnetometry, is not revealed by magnetic circular dichroism. Possible reasons for differences in magnetic response determined by magnetic circular dichroism and SQUID measurements are discussed.
17
Publication available in full text mode
Content available

Excitonic Giant Zeeman Effect in Wide Gap Diluted Magnetic Semiconductors Based on ZnO and GaN

80%
Pacuski W., Ferrand D., Kossacki P., Marcet S., Cibert J., Gaj J., Golnik A.
Acta Physica Polonica A
|
2006
|
vol. 110
|
issue 3
303-309
EN
We present a theoretical description of the excitonic giant Zeeman effect observed in wide gap diluted magnetic semiconductors (Zn,Co)O and (Ga,Mn)N. In these materials, A and B excitons present quite complex energy shifts and change of oscillator strengths under magnetic field. These features can be well reproduced using an excitonic Hamiltonian, taking into account ion-carrier exchange, wurtzite trigonal crystal field, spin-orbit and electron-hole exchange interactions.
18
Content available remote

MBE Growth and Magnetooptical Properties of (Zn,Co)Te Layers

80%
Papaj M., Kobak J., Rousset J., Janik E., Golnik A., Kossacki P., Pacuski W.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 6
1010-1011
EN
We report on epitaxial growth of diluted magnetic semiconductor (Zn,Co)Te. Reflectivity spectra reveal excitonic transition which split under magnetic field due to giant Zeeman effect. Magnetooptical effects can be described using literature data.
19
Content available remote

Influence of Sr Content on CMR Effect in Polycrystalline La_{1-x}Sr_{x}MnO_{3} Thin Films

80%
Žurauskienė N., Balevičius S., Stankevič V., Paršeliūnas J., Keršulis S., Abrutis A., Plaušinaitienė V.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 6
1136-1138
EN
The magnetoresistance of thin polycrystalline La_{1-x}Sr_{x}MnO_{3} films deposited on lucalox substrate using metal organic chemical vapor deposition technique was investigated in pulsed magnetic fields up to 18 T in the temperature range 100-320 K. The influence of film preparation conditions, ambient temperature variation and Sr content is analyzed in order to determine the optimal conditions for the design of CMR-B-scalar magnetic field sensor based on thin manganite film, operating at room temperature.
20
Content available remote

Anisotropic Magnetic Susceptibility of Neodymium Substituted SrLaAlO_{4} Crystals

80%
Fink-Finowicki J., Puźniak R., Baran M., Jabłoński R., Berkowski M., Pajączkowska A., Szymczak H.
Acta Physica Polonica A
|
1994
|
vol. 85
|
issue 3
633-637
EN
The uniaxial anisotropy of magnetic properties of SrLa_{1-x}Nd_{x}AlO_{4} single crystals (x = 0.01 and 0.05) was found from the measurements of temperature dependencies of magnetic susceptibility. Results of measurements, with magnetic field along a- and c-axis, are compared with the similar data obtained for CaNdAlO_{4} crystal. The successful description of experimental data was done in frames of the crystal field approximation. The anisotropy of magnetic susceptibility appears due to crystal field acting on magnetic neodymium ions in a system without exchange interactions.
first rewind previous Page / 2 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.