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Wyszukujesz frazę "75.50.Pp" wg kryterium: Temat


Tytuł:
A Monte Carlo Study of Critical Properties of Strongly Diluted Magnetic Semiconductor (Ga,Mn)As
Autorzy:
Tomczak, P.
Diep, H.
Jabłoński, P.
Puszkarski, H.
Powiązania:
https://bibliotekanauki.pl/articles/1030426.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.10.Nr
75.30.Hx
Opis:
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.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 514-516
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Carrier Dynamics in $Ga_{1-x}Mn_{x}As$ Studied by Resistance Noise Spectroscopy
Autorzy:
Lonsky, M.
Teschabai-Oglu, J.
Pierz, K.
Sievers, S.
Schumacher, H.
Yuan, Y.
Böttger, R.
Zhou, S.
Müller, J.
Powiązania:
https://bibliotekanauki.pl/articles/1397018.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
73.50.Td
73.50.-h
73.61.-r
64.60.ah
61.72.-y
Opis:
We report on electronic transport measurements of the magnetic semiconductor Ga_{1-x}Mn_{x}As, whereby the defect landscape in various metallic thin films (x=6%) was tuned by He-ion irradiation. Changes in the distribution of activation energies, which strongly determine the low-frequency 1/f-type resistance noise characteristics, were observed after irradiation and can be explained by deep-level traps residing in the As sublattice. Various other kinds of crystalline defects such as, for instance, Mn interstitials, which possibly form nanoscale magnetic clusters with a fluctuating spin orientation, also contribute to the 1/f noise and can give rise to random telegraph signals, which were observed in films with x=7%. In addition, we neither find evidence for a magnetic polaron percolation nor any features in the noise near the Curie temperature.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 520-522
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiband Electronic Structure of Magnetic Quantum Dots: Numerical Studies
Autorzy:
Rederth, D.
Oszwałdowski, R.
Petukhov, A.
Pientka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1029747.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.22.-f
75.50.Pp
Opis:
Semiconductor quantum dots (QDs) doped with magnetic impurities have been a focus of continuous research for a couple of decades. A significant effort has been devoted to studies of magnetic polarons (MP) in these nanostructures. These collective states arise through exchange interaction between a carrier confined in a QD and localized spins of the magnetic impurities (typically: Mn). Our theoretical description of various MP properties in self-assembled QDs is discussed. We present a self-consistent, temperature-dependent approach to MPs formed by a valence band hole. The Luttinger-Kohn k· p Hamiltonian is used to account for the important effects of spin-orbit interaction.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 343-349
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
NDT of Rating Impact of Laser Padding on the Surface Layer
Autorzy:
Napadłek, W.
Witoś, M.
Prusik, T.
Powiązania:
https://bibliotekanauki.pl/articles/1030457.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.15.Fg
03.75.Pp
81.70.Ex
81.70.Fy
75.50.Bb
06.20.-f
06.60.Mr
Opis:
The article presents the problem of quality control the paramagnetic material of weld overlays laser made on ferro- and paramagnetic materials (steels, cast iron). To assess the quality of weld overlays paramagnetic material, and also the impact of overheating, besides laboratory researches on Keyence optical microscope, used measurement of existing magnetization of magnetic field distribution. Examples of test results by magnetic memory of metals are presented. It has been found, that is expedient use magnetic methods to assess the quality the microstructure of laser pad welded surface layer (influence of heat generation, microstructure changes, chemical composition and own stresses).
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 707-709
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SWR Studies of Higher-Order Surface Anisotropy Terms in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Diep, H.
Powiązania:
https://bibliotekanauki.pl/articles/1030424.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
76.60.-k
Opis:
We extend the theory of spin-wave resonance (SWR) by introducing a new formula representing the surface pinning parameter as a series of contributions from different anisotropies existing in (Ga,Mn)As thin films. Comparing our theory with the reported experimental studies of SWR in thin films of the ferromagnetic semiconductor (Ga,Mn)As, we find that besides the first-order cubic anisotropy, higher-order cubic anisotropies (in the second and third orders) as well as uniaxial anisotropies (perpendicular in the first and second orders, and in-plane diagonal) occur on the surface of this material. To our best knowledge this is the first report of the existence of higher-order surface anisotropy fields in (Ga,Mn)As thin films.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 635-638
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics of Solid-State Synthesis of Quaternary Cu₂FeSnS₄ (Stannite) Nanocrystals for Solar Energy Applications
Autorzy:
Baláž, P.
Baláž, M.
Zorkovská, A.
Škorvánek, I.
Bujňáková, Z.
Trajić, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032135.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.05.Hd
61.46.Hk
Opis:
In this study we demonstrate the use of elemental precursors (Cu, Fe, Sn, S) to obtain stannite forms by a solid-state one-pot mechanochemical synthesis. In the processing route, we report the kinetics of the synthesis. For the characterization of the unique nanostructures, X-ray diffraction, specific surface area measurements and SQUID magnetometry methods were applied. CFTS polymorphs with the tetragonal body-centered structure with the average crystallite size 18-19 nm were obtained. The weak ferromagnetic properties of the quaternary nanocrystals after maximum milling time were also documented.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1153-1155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and structural studies of GeMnSnTe epitaxial layers
Autorzy:
Grochot, A.
Knoff, W.
Taliashvili, B.
Wołkanowicz, W.
Minikayev, R.
Pieniążek, A.
Łusakowska, E.
Sawicki, M.
Jantsch, W.
Story, T.
Przybylińska, H.
Powiązania:
https://bibliotekanauki.pl/articles/1055147.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Pp
76.50.+g
Opis:
MBE grown Ge_{1-x-y}Mn_xSn_yTe layers with Mn content ranging from 10 to 30% and Sn content ranging from 2 to 5% have been characterized with X-ray diffraction, energy-dispersive X-Ray spectroscopy, atomic force microscopy, SQUID magnetometry, and ferromagnetic resonance. All layers (except the one with the highest Mn and Sn content) were found to be single phase rhombohedral, with the distortion axis perpendicular to the layer surface, and ferromagnetic. Ferromagnetic resonance studies have shown that co-doping with a few percent of tin makes the lattice more rigid and changes considerably the magnetocrystalline anisotropy, from purely uniaxial in GeMnTe to distorted cubic in Ge_{1-x-y}Mn_xSn_yTe at the same Mn content.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 340-342
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemical Reduction of Chalcopyrite CuFeS₂: Changes in Composition and Magnetic Properties
Autorzy:
Baláž, P.
Zorkovská, A.
Baláž, M.
Kováč, J.
Tešinský, M.
Osserov, T.
Guseynova, G.
Ketegenov, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032642.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.05.Hd
Opis:
High-energy milling of sulphides with a reactive metal in so-called mechanochemical reduction mode can lead to products in nanorange and to composition which simplifies the following metallurgical processing. Chalcopyrite CuFeS₂, a ternary semiconductor with antiferromagnetic properties represents promising candidate as an advanced material for use in inexpensive nanoelectronics (solar cells, magnetic area), as well as copper ore source in metallurgical operations. In this work, the process of mechanochemical reduction of chalcopyrite with elemental iron is studied. The composition and properties of nanopowder prepared by high-energy milling were analyzed by X-ray diffraction and magnetic measurements. Most of the reaction takes place during 30 min with chalcocite Cu₂S and troilite FeS as the only reaction products. The magnetic investigations reveal significant increase of saturation magnetization as a result of milling. Unlike the conventional high-temperature reduction of chalcopyrite, the mechanochemical reduction is fast and ambient temperature and atmospheric pressure are sufficient for its propagation.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1165-1167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Off-Axis Electron Holography of Magnetic Nanostructures: Magnetic Behavior of Mn Rich Nanoprecipitates in (Mn,Ga)As System
Autorzy:
Barańska, M.
Dłużewski, P.
Kret, S.
Morawiec, K.
Li, Tian
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1033003.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.jp
68.37.Lp
07.05.Pj
75.50.Pp
Opis:
The Lorentz off-axis electron holography technique is applied to study the magnetic nature of Mn rich nanoprecipitates in (Mn,Ga)As system. The effectiveness of this technique is demonstrated in detection of the magnetic field even for small nanocrystals having an average size down to 20 nm.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1406-1408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of misfit strain in (Ga,Mn)(Bi,As) epitaxial layers on their magnetic and magneto-transport properties
Autorzy:
Levchenko, K.
Andrearczyk, T.
Domagała, J.
Sadowski, J.
Kowalczyk, L.
Szot, M.
Figielski, T.
Wosiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/1160667.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
61.05.cp
78.20.Ls
73.50.Jt
75.30.Gw
Opis:
Effect of misfit strain in the layers of (Ga,Mn)(Bi,As) quaternary diluted magnetic semiconductor, epitaxially grown on either GaAs substrate or (In,Ga)As buffer, on their magnetic and magneto-transport properties has been investigated. High-resolution X-ray diffraction, applied to characterize the structural quality and misfit strain in the layers, proved that the layers were fully strained to the GaAs substrate or (In,Ga)As buffer under compressive or tensile strain, respectively. Ferromagnetic Curie temperature and magneto-crystalline anisotropy of the layers have been examined by using magneto-optical Kerr effect magnetometry and low-temperature magneto-transport measurements. Post-growth annealing treatment of the layers has been shown to enhance the hole concentration and the Curie temperature in the layers.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-90-A-93
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(Ga,Mn)As-based magnetic tunnel junctions under electric field from first principles
Autorzy:
Luo, M.
Shen, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1058819.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Ey
75.30.Et
75.50.Pp
Opis:
Diluted magnetic semiconductors composed in magnetic tunnel junctions have potential applications in spintronics but the development has not been fast. The main difficulty is how to control the magnetism of diluted magnetic semiconductors. For our model semiconductor magnetic tunnel junctions, (Ga,Mn)As/GaAs/(Ga,Mn)As, we found that the magnetic coupling between the transition metal ions in each diluted magnetic semiconductor electrode of such semiconductor magnetic tunnel junctions can be switched from ferromagnetic to antiferromagnetic by the external electric field. The phenomenon suggest a possible avenue for the application of semiconductor magnetic tunnel junctions.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1385-1388
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Existence Conditions of Surface Spin Wave Modes in (Ga,Mn)As Thin Films
Autorzy:
Puszkarski, H.
Tomczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/1398676.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.-i
75.30.Ds
Opis:
Spin-wave resonance is a newly emerged method for studying surface magnetic anisotropy and surface spin-wave modes in (Ga,Mn)As thin films. The existence of surface spin-wave modes in (Ga,Mn)As thin films has recently been reported in the literature; surface spin-wave modes have been observed in the in-plane configuration (with variable azimuth angle $\phi_M$ between the in-plane magnetization of the film and the surface [100] crystal axis), in the azimuth angle range between two in-plane critical angles $\phi_{c1}$ and $\phi_{c2}$. We show here that cubic surface anisotropy is an essential factor determining the existence conditions of the above-mentioned surface spin-wave modes: conditions favorable for the occurrence of surface spin-wave modes in a (Ga,Mn)As thin film in the in-plane configuration are fulfilled for those azimuth orientations of the magnetization of the sample that lie around the hard axes of cubic magnetic anisotropy. This implies that a hard cubic anisotropy axis can be regarded in (Ga,Mn)As thin films as an easy axis for surface spin pinning.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 117-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Element Specific Magnetometry Combining X-ray Circular with Linear Dichroism: Fundamentals and Applications
Autorzy:
Kowalik, I.
Powiązania:
https://bibliotekanauki.pl/articles/1399311.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
78.20.Ls
75.50.Pp
75.50.Tt
Opis:
This article gives an overview of the use of X-ray absorption spectroscopy to characterize the magnetic properties for technologically important, low dimensional magnetic materials. An overview is given both for the experimental hardware, the measurements and the analysis of the spectra. The information obtained is discussed for metallic and semiconducting systems, using both the X-ray magnetic circular dichroism and the X-ray linear magnetic dichroism spectroscopy.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 831-849
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Acoustic Phonons on the Magnetic Anisotropy in GaMnAs Magnetic Semiconductors
Autorzy:
Jasiukiewicz, C.
Stagraczyński, S.
Lehmann, D.
Dugaev, V.
Berakdar, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402566.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
77.80.Fm
Opis:
We present a theoretical description of the influence of incoherent acoustic phonons on the magnetic anisotropy of magnetic semiconductors. Our theory is based on the six-band Kane model of the electron energy spectrum describing the valence band with k· p Hamiltonian including the hole-phonon interaction term. We include the effect of incoherent phonons through the hole self-energy in the six-band model, and assume a strong laser-pulse-induced flux of non-equilibrium acoustic phonons. The results of numerical calculations of magnetic anisotropy performed for (GaMn)(AsP) magnetic alloy semiconductors demonstrate the essential role of incoherent phonons.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 179-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in (Ge,Mn)Te Layers
Autorzy:
Knoff, W.
Łusakowski, A.
Wołoś, A.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/1386196.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
76.50.+g
Opis:
Ferromagnetic resonance study of magnetic anisotropy is presented for thin layers of IV-VI diluted magnetic semiconductor (Ge,Mn)Te with Mn content of 12 and 21 at.% grown by molecular beam epitaxy on BaF₂ (111) substrates. The layers with low Mn content grow in the rhombohedral crystal structure and exhibit perpendicular magnetic anisotropy whereas the layers with Mn content higher than about 20 at.% are of cubic (rock-salt) structure and show regular easy-plane type magnetic anisotropy. The quantitative analysis of the angular dependence of the ferromagnetic resonant field is performed taking into account the magnetic energy contributions due to rhombohedral distortion (axial term along the (111) growth direction of the layer) and the crystal field terms allowed for ferromagnetic systems of rhombohedral symmetry.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 404-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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