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Wyszukujesz frazę "75.10.Nr" wg kryterium: Temat


Tytuł:
Phase Transition Spin Glass-Long Magnetic Order in New Thiospinels Containing Cu, Cr and Sb
Autorzy:
Koroleva, L. I.
Demin, R. V.
Mashaev, M. Kh.
Saiflullaeva, D. A.
Virovets, T. V.
Kessler, Ya. A.
Filimonov, D. S.
Powiązania:
https://bibliotekanauki.pl/articles/1964800.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Nr
Opis:
The reentrant spin-glass transition was found in the samples of solid solutions CuCr$\text{}_{1.5+0.5x}$Sb$\text{}_{0.5-0.5x}$S$\text{}_{4}$ with x=0.34 and 0.4. The transition temperature to the spin-glass state T$\text{}_{f}$, determined from the bend on the temperature dependence of the initial susceptibility in an ac magnetic field, depends on the measurement frequency. It was shown that the dependence T$\text{}_{f}$(ω) obeys the power law 1/ω=(1/ω$\text{}_{0}$)[T$\text{}_{f}$/(T$\text{}_{f}$ - T*)]$\text{}^{zν}$ assuming existence of the phase transition at T*. The maximum of the temperature dependence of electroresistivity was found for the sample with x=0.34 in T* region. These facts show that considered spin-glass-long magnetic order transition is the phase transition.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 441-444
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Possible Analogy between Spin-Glasses and Systems
Autorzy:
Łusakowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1920977.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Nr
71.55.Dp
Opis:
An analogy between a spin-glass and a material containing DX centers is postulated. The basis of the analogy is the formal identity of the Hamiltonians of these two systems. A correspondence between parameters of the spin-glass and of the DX system is established. Experiments which could support the above idea are proposed.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 620-622
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kondo Lattice Models for Rare-Earth and Actinide Systems
Autorzy:
Coqblin, B.
Powiązania:
https://bibliotekanauki.pl/articles/1426694.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
75.10.Nr
75.30.Nr
Opis:
We present here some works on the strong competition between the Kondo effect, magnetic order and eventually spin glass or frustration effect in anomalous rare-earth and actinide systems. First, we develop an underscreened Kondo lattice model with $S_{f}$ = 1 spins for the 5f-electrons and we have recently improved it by deriving, by the Schrieffer-Wolff transformation, a 5f-band with a finite bandwidth. The underscreened Kondo lattice model can account for properties of some uranium and neptunium compounds, like UTe, $Np_2PdGa_3$ or $UCu_2Si_2$ which have a large Curie temperature $T_{c}$ of order 100 K and present also a Kondo behavior. In particular, we can account for the observed maximum of $T_{c}$ under pressure in UTe and the magnetization curves of $NpNiSi_2$ showing the occurrence of the Kondo effect at low temperatures below $T_{c}$. Second, we have studied the properties of disordered cerium alloys like $CeCu_xNi_{1-x}$ or $CeRh_xPd_{1-x}$ by considering the Kondo effect, a ferromagnetic order and a spin glass behavior described by several approaches. The van Hemmen approach gives a good explanation of the properties of cerium alloys and we are describing the magnetic glass clusters which occur in both spin glass and ferromagnetic phases. Third, we present a new description of a frustrated Kondo lattice model, which can account for the behavior under pressure or doping of some ytterbium compounds like $Yb_2Pd_2Sn$ and YbAgGe.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1005-1013
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Neural Network Model of an Ising Spin Glass
Autorzy:
Wilson, K. F.
Goossens, D. J.
Powiązania:
https://bibliotekanauki.pl/articles/2013998.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.-b
75.10.Nr
84.35.+i
Opis:
The behaviour of an Ising spin glass (S=1/2) with infinite range interactions is modelled using a numerical simulation based on a neural network. Thermodynamic variables are defined on the network, and are found to obey the Thouless-Anderson-Palmer theory when the applied magnetic field is zero. When a magnetic field is applied along the spin direction, complex field-dependent behaviour appears, including a state in which the Edwards-Anderson order parameter is independent of temperature below the critical temperature.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 983-986
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Frustration in Some Magnetic Compounds
Autorzy:
Szytuła, A.
Gondek, Ł.
Penc, B.
Hernandez-Velasco, J.
Powiązania:
https://bibliotekanauki.pl/articles/2038386.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Nr
75.25.+z
75.50.Ee
Opis:
In the paper the results of the powder neutron diffraction measurements of RAuIn (R = Ce, Tb, Dy, and Er) and ZnFe$\text{}_{2}$O$\text{}_{4}$ compounds at low temperatures are presented. For the RAuIn compounds, which crystallize in the hexagonal ZrNiAl-type structure, the rare-earth moments lie in the ab-plane and form a typical triangle non-collinear structure. ZnFe$\text{}_{2}$O$\text{}_{4}$ has the normal spinel structure in which the Fe$\text{}^{3+}$ ions occupy the B sites, forming the corner-shared tetrahedra of the Fe spins. At low temperatures experimental data indicate the coexistence of the long-range and the short-range magnetic order. The obtained results suggest that the important factor which influences the magnetic ordering in these compounds is geometrical frustration of magnetic moments.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 583-591
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Spin Glass State in S=3/2 Kagomé Antiferromagnet $Co(N_{3})_{2}(bpg)[(CH_{3})_{2}(NCOH)]_{4/3}$
Autorzy:
Vrábel, P.
Čižmár, E.
Orendáčová, A.
Gao, S.
Orendáč, M.
Powiązania:
https://bibliotekanauki.pl/articles/1368680.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.30.Et
75.10.Nr
Opis:
Specific heat, magnetic susceptibility and magnetization of $Co(N_{3})_{2}(bpg)[(CH_{3})_{2}(NCOH)]_{4/3}$, representing S=3/2 kagomé system are reported. Long-range ordering at 16 K was revealed, however, at lower temperatures slow spin dynamics is still found. The analysis of alternating susceptibility suggests the onset of glassy state. The study of the time dependence of magnetization revealed the existence of more relaxation channels with pronounced different relaxation times. The observed behaviour is consistent with the formation of topological spin glass in which relaxation is governed by both spin and chiral degrees of freedom.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 266-267
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Coupling and Exchange Bias in FM/AFM Bilayers for a Fully Compensated AFM Interface
Autorzy:
Skubic, B.
Hellsvik, J.
Nordström, L.
Eriksson, O.
Powiązania:
https://bibliotekanauki.pl/articles/1810281.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Lk
75.40.Mg
75.10.Nr
Opis:
We address the interlayer coupling in a ferromagnet/antiferromagnet bilayer where the interface of the antiferromagnet is fully compensated. We discuss the role of different types of exchange interaction for the interlayer coupling and exchange bias. We propose two types of corrections to the ideal Heisenberg Hamiltonian which may explain exchange bias. The first is a correction for the angular dependence of the exchange interactions and the second a correction due to magnetostriction and interface imperfections. The first correction contributes to an anisotropy at the interface and favors either parallel or perpendicular coupling across the interface. The second correction contributes to the exchange bias. Our analysis is based on atomic spin dynamics simulations, and our results show that small corrections to the ideal Heisenberg Hamiltonian may have macroscopic consequences in systems with frustrated interatomic interactions.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 25-29
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ground-State Energy of a Frustrated ±J Ising Model on a Strip of Squares
Autorzy:
Błaszyk, M.
Fechner, B.
Powiązania:
https://bibliotekanauki.pl/articles/2013704.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
We investigated a ±J Ising model on an infinite strip of squares of the width of one and two bonds with a random distribution of ferro- and antiferromagnetic exchange interactions. The exact ground-state energy as a function of the concentration of antiferromagnetic bonds was derived and its singular points in the complex-plane were found.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 855-858
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Method of Linear Equations for Nonzero Temperatures in One-Dimensional Ising Models
Autorzy:
Błaszyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/2041822.pdf
Data publikacji:
2005-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
The method of linear equations was applied to nonzero temperatures. Two models were considered. The first is the disordered model of random ferromagnetic and antiferromagnetic integrals whose transition matrix meets the condition of invariance of the sum of terms in each line. Although the other model (one-dimensional Ising model in an external field) is devoid of disorder it does not require any assumptions on the form of the transition matrix.
Źródło:
Acta Physica Polonica A; 2005, 107, 3; 451-457
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
One-Dimensional Spin Glass
Autorzy:
Błaszyk, M.
Fechner, B.
Powiązania:
https://bibliotekanauki.pl/articles/2046876.pdf
Data publikacji:
2006-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
Thermodynamics of one-dimensional finite-ranged Ising model with quenched disorder introduced by random admixture of bonds with second neighbours by means of transfer-matrix method was determined. The influence of frustrations and competition on the internal energy, specific heat, correlations functions, and susceptibility was studied.
Źródło:
Acta Physica Polonica A; 2006, 110, 1; 11-24
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetisation and Entropy of a One-Dimensional±J Ising Model in a Uniform Magnetic Field
Autorzy:
Błaszyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/2047254.pdf
Data publikacji:
2007-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
An approximation scheme related to the averaging procedure over finite fragments of the lattice was proposed. The magnetisation and entropy were calculated numerically. The correctness of this approximation scheme was analysed against the magnetic field and temperature.
Źródło:
Acta Physica Polonica A; 2007, 111, 2; 191-200
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
One-Dimensional Time-Dependent Frustrated and Disordered Ising Model
Autorzy:
Błaszyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1812030.pdf
Data publikacji:
2008-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
The dynamics being modifications of the Glauber one were proposed. The time course of the single spin and two-spin correlation function was determined. These calculations were performed for ordered systems, although a possibility of their extension over disordered ones was indicated.
Źródło:
Acta Physica Polonica A; 2008, 114, 4; 657-666
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Properties of One-Dimensional ± J Ising Models on Square Lattices
Autorzy:
Błaszyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1808002.pdf
Data publikacji:
2009-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
The energies and entropies of the one-dimensional ± J Ising models on square lattices have been compared. The method proposed in this paper explains the impossibility of getting exact results in nonzero temperatures and specifies the conditions of error minimisation.
Źródło:
Acta Physica Polonica A; 2009, 115, 5; 849-853
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Ground State of Ising Model±J on the Tube
Autorzy:
Błaszyk, Marian
Powiązania:
https://bibliotekanauki.pl/articles/2036873.pdf
Data publikacji:
2003-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Nr
75.50.Lk
Opis:
A method of linear equations is proposed allowing a reduction of a physical problem of determination of energy, entropy, or magnetisation for the systems with frozen disorder to a mathematical problem of solving a set of linear equations. Apart from an exact method for determination of energy and entropy, a type of the mean field approach is presented, which permits a summation over series representing entropy. Moreover, it was established that magnetisation can appear only when the antiferromagnetic integrals occur at the zero probability.
Źródło:
Acta Physica Polonica A; 2003, 104, 1; 3-24
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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