Temat: DG - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Heisenberg Model of a Ferromagnetic Monolayer Deposited on a Non-Magnetic Bulk Substrate
Autorzy:: Jaworski, W.
Powiązania:: https://bibliotekanauki.pl/articles/1810418.pdf
Data publikacji:: 2009-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Dg
75.10.Hk
75.10.Jm
Opis:: A model describing a Heisenberg ferromagnetic monolayer (in a magnetic field) interacting with its non-magnetic bulk substrate is formulated. We use reduced-density operators to show that physical properties of the monolayer are affected by its interaction with the environment. Particularly the influence of the substrate lattice vibrations on the monolayer exchange parameter is examined. The Gaussian-type orbitals were used to calculate the distance dependence of the exchange parameter and the many-body Green functions to calculate the temperature dependence of the magnetization. Finally, the influence of the Debye temperature of the substrate on the magnetization of the monolayer is depicted. Although the resultant effect is not prominent, we state that interaction of ultrathin magnetic films with their environment has to be taken into account in the construction of the reduced-density operator.
Źródło:: Acta Physica Polonica A; 2009, 115, 1; 171-173
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Gaussian Fluctuations of Two Molecular Fields in the Blume-Emery-Griffiths Model
Autorzy:: Jaworski, W.
Jacyna-Onyszkiewicz, Z.
Powiązania:: https://bibliotekanauki.pl/articles/1505093.pdf
Data publikacji:: 2011-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Dg
75.10.Hk
75.10.Jm
Opis:: The Blume-Emery-Griffiths model for spins S=1 in a bilayer with z=5 nearest neighbours is studied with the use of Gaussian fluctuations approximation. The fluctuations of two molecular fields, connected with two order parameters, are introduced. Their influence on phase diagrams for non-negative values of the biquadratic coupling constant is taken under consideration. The results are compared with those obtained by the mean-field approximation and discussed.
Źródło:: Acta Physica Polonica A; 2011, 119, 6; 846-849
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Full Susceptibility Tensor for Localized Spin Models with S = 1, 3/2, 2, 5/2 and with Rhombic Anisotropy
Autorzy:: Pełka, R.
Powiązania:: https://bibliotekanauki.pl/articles/1505395.pdf
Data publikacji:: 2011-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Dg
75.10.Jm
75.30.Gw
75.50.Xx
Opis:: A general discussion of the simulation procedure of the full susceptibility tensor and isothermal magnetization pseudovector for compounds comprising weakly-interacting magnetic centers is presented. A single-crystal-sample as well as a powder-sample case are considered. The procedure is used to obtain explicit expressions for the full susceptibility tensor for spins S = 1, 3/2, 2, and 5/2 for non-vanishing rhombic local anisotropy and any form of spectroscopic tensor.
Źródło:: Acta Physica Polonica A; 2011, 119, 3; 428-436
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Direct Simulations of the Quantum Model for CsNiF$\text{}_{3}$
Autorzy:: Caramico D'Auria, A.
Esposito, F.
Esposito, U.
Kamieniarz, G.
Dekeyser, R.
Powiązania:: https://bibliotekanauki.pl/articles/1930597.pdf
Data publikacji:: 1994-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 64.60.Cn
75.10.Dg
75.10.Jm
75.40.Cx
75.40.Mg
Opis:: We address the problem of reliability of a finite-chain technique for CsNiF$\text{}_{3}$. We investigate the effect of the boundary conditions, completely neglected so far, and apply a new extrapolation procedure appropriate for quantities showing non-monotonic behaviour. From a detailed analysis of the specific heat existing theoretical estimates for the model parameters are discriminated and a strong evidence for the reliability of the direct finite-chain technique predictions is presented.
Źródło:: Acta Physica Polonica A; 1994, 85, 2; 409-412
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Effective Field Methods for Magnetic Systems
Autorzy:: Kamieniarz, G.
Dekeyser, R.
Musiał, G.
Powiązania:: https://bibliotekanauki.pl/articles/1930600.pdf
Data publikacji:: 1994-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 64.60.Cn
64.60.Fr
05.50.+q
75.10.Dg
75.10.Hk
75.10.Jm
75.40.Cx
75.40.Mg
Opis:: The self-consistency conditions inherent in the mean-field approximation are extended to take into account some pair correlations. Ii is shown that this extension is systematically improvable and applicable to the spin systems with short-range interactions in the entire temperature region. With two correlations included and the renormalization-group ideas implemented, the critical properties of the Ising model are satisfactorily revealed. Moreover, the improved estimates of the thermodynamical quantities for the quantum linear XY model from the finite-size calculations are found down to very low temperatures.
Źródło:: Acta Physica Polonica A; 1994, 85, 2; 413-417
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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