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Wyszukujesz frazę "75.70.Ak" wg kryterium: Temat


Tytuł:
Calculation of Oscillatory Exchange in bcc-Fe/Cu Multilayers
Autorzy:
Krompiewski, S.
Pirnay, J.
Krey, U.
Süss, F.
Tematy:
75.70.Ak
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1930614.pdf  Link otwiera się w nowym oknie
Opis:
Within a tight-binding LMTO approach in the atomic sphere approximation we calculate the exchange interaction, J, between magnetic Fe slabs in a periodic multilayer arrangement m Fe/n Cu/ .... We concentrate on cases, where Cu adapts to the bcc structure of Fe. For the "open" (100)-interface our results suggest that a minimal number of m = 13 Fe monolayers per Fe slab is necessary to get antiferromagnetic coupling. For m = 16 we find antiferromagnetic coupling for 8 ≤ n ≤ 14, i.e. a long period of ca. 11 and a short period of 2 Cu monolayers. In contrast, for the (110)-interfaces, only a long period of 14 monolayers is found, i.e. the coupling is antiferromagnetic for 7 ≤ n ≤ 14 already for small values of m. We then model the roughness by mutual interchange of 50% of the Fe and Cu atoms, respectively, in the interface layers and find that, due to the interchange, the coupling constant J, as a function of the Cu-spacer thickness n, roughly shifts by half a mono-layer to the right. In the (100)-case, the short period gets washed out by the roughness.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoelastic Effects and Magnetic anisotropy in Superlattice System
Autorzy:
Jaroszewicz, R.
Bąk, Z.
Tematy:
75.70.Cn
75.70.Ak
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1955483.pdf  Link otwiera się w nowym oknie
Opis:
In this contribution, we will discuss the effect of interface misfit strain on magnetic coupling of ferromagnetic layers, across intervening, metallic spacer in the epitaxial superlattice system. We calculate the interface lateral lattice deformation, due to ionic radii misfit within the Frenkel-Kontorova model and derive its influence on surface magnetic anisotropy and electronic properties of the nonmagnetic spacer. We will study also the origin of the interface magnetoelastic asymmetry in superlattices and its effect on magnetic coupling between magnetic layers. Also the magnetoelastic contribution to the in-plane exchange coupling is widely discussed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Peculiar Properties of Ultrathin fcc Iron Films Epitaxially Grown on Cu(001)
Autorzy:
Wojnecki, R.
Sukiennicki, A.
Tematy:
75.70.Ak
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/2013292.pdf  Link otwiera się w nowym oknie
Opis:
Very peculiar electronic structure and local magnetic moment distribution for fcc Fe ultrathin films of 1, 2, 3, and 4 monolayers of thickness, epitaxially grown on Cu(001) substrates and covered with some layers of Cu, are calculated. The lattice constant of the Fe film is assumed to be equal to that of Cu, homogeneously in the whole film. The competition between the surface ferromagnetism and bulk antiferromagnetism results in ferromagnetism of 2-monolayer film, asymmetric solution for 3-monolayer film and antisymmetric solution for 4-monolayer film.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Electronic Structure and Magnetic Behaviour of FCC Iron Films Epitaxially Grown on Cu(001)
Autorzy:
Wojnecki, R.
Sukiennicki, A.
Tematy:
75.70.Ak
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1968917.pdf  Link otwiera się w nowym oknie
Opis:
Electronic structure and local magnetic moments for the epitaxially grown fcc Fe films included between the Cu(001) substrate and Cu(001) covering layers are calculated. The lattice constant of the Fe film is assumed to be equal to that of Cu homogeneously in the whole film. Interface parts of the Fe film are found to be ordered ferromagnetically, while inner part of the Fe film is obtained as ordered layer-by-layer antiferromagnetically for odd number of layers. For even number of Fe layers the most favourable configuration includes antiferromagnetism of inner layers with two middle layers coupled ferromagnetically.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gaussian Fluctuations of Molecular Field in Quasi-One-Dimensional Ising Model
Autorzy:
Onyszkiewicz, Z.
Wierzbicki, A.
Tematy:
75.10.Hk
75.70.Ak
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/2007877.pdf  Link otwiera się w nowym oknie
Opis:
Quasi-one-dimensional spin systems described by an Ising-like Hamiltonian with a strong space anisotropy (s=1/2) are investigated. Magnetic properties of this model are examined in the approximation including Gaussian fluctuations of molecular field. This paper reports an attempt at obtaining more accurate results for Gaussian fluctuation of molecular field by an exact formula for mean fluctuations of a spin.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy in Eus-pbs Multilayers
Autorzy:
Story, T.
Swüste, C. H. W.
Swagten, H. J. M.
de Jonge, W. J. M.
Stachow-Wójcik, A.
Twardowski, A.
Arciszewska, M.
Dobrowolski, W.
Gałązka, R. R.
Sipatov, A. Yu.
Tematy:
75.50.Pp
75.70.Ak
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/2013042.pdf  Link otwiera się w nowym oknie
Opis:
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$\text{}_{2}$ 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$\text{}_{V}$+2K$\text{}_{S}$/d , with the surface term K$\text{}_{S}$ larger for layers grown on BaF$\text{}_{2}$ 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.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalization of Magnetostatic Method of Moments for Thin Layers with Regular Rectangular Grids
Autorzy:
Szewczyk, R.
Tematy:
75.70.Ak
75.50.Kj
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1032670.pdf  Link otwiera się w nowym oknie
Opis:
Possibilities of the modeling of the flux density distribution in thin films are significantly limited using the finite elements method due to the fast increase of the number of tetrahedral elementary cells with reduction of the thickness. For this reason, method of the moments is very important alternative for finite elements method in the case of thin layers, where layer's thickness should be considered. Method of the moments overcomes this barrier, due to the possibility of operation on uniform grids with limited number of cells. Moreover, in opposite to the finite elements method, the method of the moments requires solving of the well defined linear equations, instead of the set of ill-posed differential equations. Paper presents the generalization of the method of the moments for thin layers with given thickness. Layers are defined as the 2D rectangular grids. Within the generalization, four key equations describing the influence of rectangular cell's border on the magnetization of cells are stated. On the base of these dependences, the set of 2NM linear equations was determined, where N and M are the numbers of rectangular cells in the rows and columns of regular grid. Finally, the set of linear equations is solved and magnetic flux density distribution in the thin layer is calculated.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thickness Dependent Magnetic Properties of Polycrystalline Nickel Thin Films
Autorzy:
Parlak, U.
Aköz, M.
Tokdemir Öztürk, S.
Erkovan, M.
Tematy:
75.70.Ak
75.30.Gw
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1192388.pdf  Link otwiera się w nowym oknie
Opis:
Magnetization directions of ferromagnetic ultra-thin films can be altered by increasing the thickness. The transition between in-plane and out-of-plane axes is induced by the competition among the magnetostatic, magnetocrystalline and magnetoelastic anisotropy energies. Such an effect has attracted more interest recently, due to the applications in magneto-optical recording technologies. In this study, we have investigated by magneto-optical Kerr effect the magnetization properties of magnetron sputtered nickel thin films.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Bias in Ni-Mn-Sn Heusler Alloy Films
Autorzy:
Gościańska, I.
Załęski, K.
Głowiński, H.
Kudryavtsev, Yu.
Dubowik, J.
Tematy:
75.70.Ak
75.30.Et
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1427549.pdf  Link otwiera się w nowym oknie
Opis:
We report a relatively large exchange bias effect observed for the first time in Ni-Mn-Sn thin films with different microstructure and composition: a $Ni_{50}Mn_{36}Sn_{14}$ epitaxial film (A), a $Ni_{50}Mn_{43}Sn_7$ film which is phase decomposed (B), and a $NiMn//Ni_{50}Mn_{25}Sn_{25}$ bilayer (C). Despite the samples differ markedly in both microstructure and composition $H_{EB}$ does not substantially differs at 5 K. Exchange bias decreases with increasing T approximately as $H_{EB}$ (T) ∝ $H_{EB}$ (5K)/T with $H_{EB}$ (5K) of 180 Oe and 60 Oe for sample B and C, respectively and almost linearly for sample A with $H_{EB}$ (5K) = 65 Oe. Blocking temperature where the exchange bias vanishes is 40, 50 and 80 K for sample A, C and B, respectively. The results suggest that the role of AFM/FM interfaces is not substantial in formation of exchange bias in Ni-Mn-Sn Heusler alloy films and exchange bias is rather related to AFM/FM interactions in nanoscale.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface and Thin Film Magnetization of Isotropic and Anisotropic Heisenberg Ferromagnet at Low Temperatures
Autorzy:
Modrak, P.
Tematy:
75.70.Ak
75.30.Pd
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1968931.pdf  Link otwiera się w nowym oknie
Opis:
The independent random walk method (which is equivalent to the noninteracting spin wave method) with no further approximations was used to calculate the low temperature expansion of: (i) the local mean spin values of an isotropic Heisenberg ferromagnet for semi-infinite crystal and (ii) the spontaneous magnetization of an anisotropic Heisenberg ferromagnet for monolayer and double layer. The full low temperature expansion starting with T$\text{}^{3}\text{}^{/}\text{}^{2}$ term was obtained for the semi-infinite Heisenberg ferromagnet and it was shown that the spontaneous magnetization for thin films of anisotropic Heisenberg ferromagnets can exhibit a quasi-linear behaviour in certain temperature region related to the magnitude of the anisotropy.
Dostawca treści:
Biblioteka Nauki
Artykuł

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