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Tytuł:
One-Dimensional Time-Dependent Ising Model in an External Magnetic Field
Autorzy:
Błaszyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1808075.pdf
Data publikacji:
2009-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
Opis:
The relaxation process, through which the inequilibrium state described by the Ising model reaches the equilibrium state, was proposed. The process is defined by the action of the transition matrix on the vector of state and the demand of its normalisation. It is assumed that in the state of inequilibrium the vector of state has the same functional dependence as the eigenvector of the transition matrix corresponding to the highest eigenvalue. Two cases are considered: when the cell under transformation is composed of one or two sites. The calculations were performed for a uniform initial state. For the two cases of one and two-site cells the modes of reaching the equilibrium state via magnetisation were compared. When the external magnetic field and temperature tend to zero, both magnetisation and the correlation function of the nearest neighbours show the critical slowing down phenomenon.
Źródło:
Acta Physica Polonica A; 2009, 115, 3; 617-621
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differential Operator Technique in the Ising Spin Systems
Autorzy:
Kaneyoshi, T.
Powiązania:
https://bibliotekanauki.pl/articles/1929335.pdf
Data publikacji:
1993-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.-b
Opis:
A review is given of the differential operator technique in the Ising spin systems. The theoretical frameworks of the various models are discussed on the basis of the Ising spin identities. These can be applied to examine the magnetic properties in a variety of magnetic materials.
Źródło:
Acta Physica Polonica A; 1993, 83, 6; 703-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Magnetostriction in Disordered 2D Ising Ferromagnets
Autorzy:
Kawecka-Magiera, B.
Maksymowicz, A.
Kułakowski, K.
Lenda, A.
Powiązania:
https://bibliotekanauki.pl/articles/1955466.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.80.+q
Opis:
We investigate volume and shape magnetoelastic strains of a 2D anisotropic Ising alloy with partial atomic order. Three possible origins of shape strain are distinguished: (i) anisotropy of elastic constants, (ii) anisotropy of magnetic bonds and (iii) anisotropy of the spatial derivatives of magnetic bonds. None of these mechanisms vanishes above the Curie temperature. Equilibrium strains are expressed in terms of anisotropic spin-spin nearest-neighbours correlation functions. These functions are calculated against temperature, both in ferromagnetic and paramagnetic phase. Shape strain decreases monotonously with temperature for the mechanisms (i) and (iii), and has a maximum near the Curie temperature for the case (ii). The results may be relevant for multilayer magnetic systems.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 297-301
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Standard Statistical Thermodynamics with Generalized Statistical Thermodynamics Results for Ising Chain
Autorzy:
Tirnakli, U.
Demirhan, D.
Büyükkiliç, F.
Powiązania:
https://bibliotekanauki.pl/articles/1964226.pdf
Data publikacji:
1997-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.20.-y
Opis:
In this study, the internal energy and the specific heat of the one-dimensional Ising model obtained in the frame of the generalized statistical thermodynamics by Andrade, were somewhat extended and compared with the internal energy and the specific heat which were calculated in the standard (conventional) statistical thermodynamics. In the q → 1 case, approaching of the generalized internal energy and the specific heat to the standard well-known results, were illustrated by numerical applications. In addition to these, N ≫ 1 case was also investigated.
Źródło:
Acta Physica Polonica A; 1997, 91, 6; 1135-1042
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Statistical Properties of the Rough Surface
Autorzy:
Balcerzak, T.
Powiązania:
https://bibliotekanauki.pl/articles/1929299.pdf
Data publikacji:
1993-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
68.35.Md
Opis:
The temperature induced roughening of the solid surface is described by means of a discrete Gaussian model, using integral operator technique. On the basis of the exact statistical identities, the formulae for several local moments, i.e. ⟨hi⟩), ⟨(hi)$\text{}^{2}$⟩ and ⟨hihj⟩ are derived. The results of computer calculations, including surface specific heat, are presented for three lattices with z = 3, 4, and 6. In discussion, some further applications of the presented method are suggested.
Źródło:
Acta Physica Polonica A; 1993, 83, 5; 597-610
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Diamond Model of Social Response within an Agent-Based Approach
Autorzy:
Nail, P.
Sznajd-Weron, K.
Powiązania:
https://bibliotekanauki.pl/articles/1398893.pdf
Data publikacji:
2016-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.23.Ge
05.50.+q
Opis:
Models of social response concern the identification and delineation of possible responses to social pressure. Most models are based on simple one-dimensional conceptualizations of conformity and its alternatives even though more sophisticated models have been available for a number of years. The diamond model is perhaps the most refined of the two-dimensional formulations. It is particularly useful in building agent-based models of opinion dynamics because it gives clear and explicit operational definitions of basic types of social response. In fact, the diamond model is actually a ready recipe for a microscopic model of opinion dynamics. Moreover, it fits quite well Einstein's simple but no simpler strategy. In this work, we will present the logic of the diamond model as well as its implications for agent-based modeling.
Źródło:
Acta Physica Polonica A; 2016, 129, 5; 1050-1054
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reentrant Transitions of Ising-Heisenberg Ferromagnet on a Triangular Lattice with Diamond-Like Decorations
Autorzy:
Jaščur, M.
Strečka, J.
Čanová, L.
Powiązania:
https://bibliotekanauki.pl/articles/1813798.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
68.35.Rh
Opis:
The mixed spin-1/2 and spin-1 Ising-Heisenberg ferromagnet on the decorated triangular lattice consisting of inter-connected diamonds is investigated within the framework of an exact decoration-iteration mapping transformation. It is shown that the diamond-like decoration by a couple of the Heisenberg spins gives rise to a diverse critical behaviour including reentrant phase transitions with two consecutive critical points.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 453-456
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific Heat of the Mixed Spin-1/2 and Spin-S Ising Model with a Rope Ladder Structure
Autorzy:
Kiššová, J.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813792.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.40.Cx
Opis:
The mixed spin-1/2 and spin-S (S>1/2) Ising model on a rope ladder is examined by combining two exact analytical methods. By the decoration-iteration mapping transformation, this mixed-spin system is firstly transformed to a simple spin-1/2 Ising model on the two-leg ladder, which is then exactly solved by the standard transfer-matrix method. The thermal variations of the zero-field specific heat are discussed in particular.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 445-448
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Existence of p-Adic Quasi Gibbs Measures for Mixed Type p-Adic Ising λ-Model
Autorzy:
Dogan, M.
Akin, H.
Mukhamedov, F.
Powiązania:
https://bibliotekanauki.pl/articles/1398800.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
02.20.Qs
Opis:
We consider nearest-neighbors and next nearest-neighbors p-adic Ising λ-model with spin values {∓ 1} on a Cayley tree of order two. First we prove that the model satisfies the Kolmogorov consistency condition and then we prove that the nonlinear equation corresponding to the model has at least two solutions in $Q_{p}$, where p is a prime number p ≥ 3. One of the roots is in $ε_{p}$ and the others are in $Q_{p}$\$ε_{p}$. If the nonlinear equation has more than one non-trivial solutions for the model then we conclude that p-adic quasi Gibbs measure exists for the model.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 861-864
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Spin-1/2 Ising Model on the Bow-Tie Lattice as an Exactly Soluble Free-Fermion Model
Autorzy:
Strečka, J.
Čanová, L.
Powiązania:
https://bibliotekanauki.pl/articles/1813800.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
68.35.Rh
Opis:
The spin-1/2 Ising model on the bow-tie lattice is exactly solved by establishing a precise mapping relationship with its corresponding free-fermion eight-vertex model. Ground-state and finite-temperature phase diagrams are obtained for the anisotropic bow-tie lattice with three different exchange interactions along three different spatial directions.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 457-460
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:
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:
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:
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:
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 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
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 Effect of a Random Crystal-Field on the Mixed Ising Spins (1/2, 3/2)
Autorzy:
Bahmad, L.
Benayad, M.
Benyoussef, A.
El Kenz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1504480.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Hk
75.50.Gg
Opis:
We study the magnetic properties of a mixed Ising ferrimagnetic system, in which the two interacting sublattices have spins σ,(±1/2) and spins S,(±3/2,±1/2) in the presence of a random crystal field, with the mean field approach. The results obtained, using mean field approach and Monte Carlo simulation, show the appearance of a new ferrimagnetic phase, namely the partly ferrimagnetic phase ($m_{σ}$ = -1/2 , $m_{S}$ = +1). Consequently, three topologically different types of phase diagrams have been given by mean field approach. The effect of increasing the exchange interaction parameter J, at very low temperature is also investigated.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 740-746
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulated Annealing with Tsallis Weights for ±J Spin Glass
Autorzy:
Kłos, J.
Kobe, S.
Powiązania:
https://bibliotekanauki.pl/articles/2013971.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.Cn
75.10.Hk
Opis:
Recently, on the basis of the Tsallis distribution of states the generalized Monte Carlo acceptance probabilities have been proposed and applied to various optimization problems. In the paper we used the generalized simulated annealing algorithms for the ±J spin glass model. Efficiency of the new annealing procedures was compared with that of the conventional methods. This was done with respect to the number of annealing steps and to the lowest energy found. The algorithms were applied to a system of 70×70 spins on a square lattice with periodical boundary conditions whose ground state configurations are known exactly. This enables us to evaluate the efficiency in a quantitative way.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 943-946
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Study of the Frustrated Ising Antiferromagnet on the Honeycomb Lattice
Autorzy:
Bobák, A.
Lučivjanský, T.
Žukovič, M.
Borovský, M.
Balcerzak, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032632.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.-a
75.10.Hk
Opis:
We study effects of the next-next-nearest-neighbour antiferromagnetic (J₃ < 0) interaction on critical properties (or phase diagram) of the frustrated spin-½ J₁-J₂-J₃ Ising antiferromagnet on the honeycomb lattice by using the effective-field theory with correlations. Beside the ground-state energy, we find that there is a region of J₃ < 0 in which the frustrated honeycomb lattice antiferromagnet exhibits a tricritical point, at which the phase transition changes from the second order to the first one on the line between Néel antiferromagnetic and paramagnetic phases.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 636-638
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Exact Solution of the Mixed-Spin Ising Chain with Axial and Rhombic Zero-Field Splitting Parameters
Autorzy:
Dančo, M.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1506905.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.Jk
75.10.Pq
Opis:
Ground-state phase diagram of the mixed spin-1/2 and spin-1 Ising chain with axial and rhombic zero-field splitting parameters is exactly calculated within the framework of the transfer-matrix method. It is shown that the rhombic zero-field splitting parameter prefers the magnetically ordered phase instead of the disordered phase.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 728-729
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ground-State Phase Diagram of Geometrically Frustrated Ising-Heisenberg Model on Doubly Decorated Planar Lattices
Autorzy:
Čanová, L.
Strečka, J.
Dely, J.
Jaščur, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813794.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Hk
75.10.Jm
Opis:
Ground-state phase diagram of the mixed spin-1/2 and spin-1 Ising-Heisenberg model on doubly decorated planar lattices is examined using the generalized decoration-iteration transformation. The main attention is devoted to the comparison of the ground-state properties of the quantum Ising-Heisenberg model and its semi-classical Ising analogue.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 449-452
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Phase Diagrams of Spin-1/2 Ising Model on a Two-Layer Bethe Lattice with AFM/AFM Interactions
Autorzy:
Albayrak, E.
Yigit, A.
Powiązania:
https://bibliotekanauki.pl/articles/1807767.pdf
Data publikacji:
2009-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
68.35.Rh
64.60.Cn
Opis:
The phase diagrams of spin-1/2 Ising model on a two-layer Bethe lattice with antiferromagnetic interactions for each layer and either antiferromagnetic or ferromagnetic interaction between the layers are investigated by using the pairwise approach for given values of coordination number q. The exact expressions of the order-parameters, response functions and free energy are obtained in terms of the recursion relations. The ground-state phase diagrams are calculated for given system parameters of the model. In the guidance of the ground-state phase diagrams, the temperature dependent phase diagrams of the model are also studied in detail for given coordination numbers q = 3, 4 and 6. It was found that the system presents only second-order phase transitions with different thermal behaviors for all values of q. In addition, two Néel temperatures, $T_{N}$, are found for q = 6 only.
Źródło:
Acta Physica Polonica A; 2009, 116, 2; 127-134
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Study of Weak Ferromagnetism in 2D J$\text{}_{1}$-J$\text{}_{2}$ Heisenberg Model with Dzyaloshinskii-Moriya Interaction
Autorzy:
Voigt, A.
Richter, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955526.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
05.50.+q
75.10.Jm
Opis:
By means of exact diagonalization we consider the groundstate of the J$\text{}_{1}$-J$\text{}_{2}$ spin 1/2 Heisenberg model with an anisotropic interaction term of Dzyaloshinskii-Moriya type. We find that a Dzyaloshinskii-Moriya interaction may create a weak ferromagnetic moment. The interplay between the quantum nature of the groundstate of the pure J$\text{}_{1}$-J$\text{}_{2}$ model and the anisotropic Dzyaloshinskii-Moriya interaction favour energetically a well-defined direction of spin alignment creating anisotropic correlations.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 371-375
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Competing Interactions on a Cayley Tree-Like Lattice: Pentagonal Chandelier
Autorzy:
Uguz, S.
Ganikhodjaev, N.
Akin, H.
Temir, S.
Powiązania:
https://bibliotekanauki.pl/articles/1490904.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.De
Opis:
Different types of lattice spin systems with competing interactions have rich and interesting phase diagrams. In this study we present some new results for such systems involving the Ising spin system (i.e. σ = ± 1) using a generalization of the Cayley tree-like lattice approximation. We study the phase diagrams for the Ising model on a Cayley tree-like lattice, a new lattice type called pentagonal chandelier, with competing nearest-neighbor interactions $J_1$, prolonged next-nearest-neighbor interactions $J_{p}$ and one-level next-nearest-neighbor senary interactions $J_{l_1}^{(6)}$. The colored phase diagrams contain some multicritical Lifshitz points that are at nonzero temperature and many modulated new phases. We also investigate the variation of the wave vector with temperature in the modulated phase and the Lyapunov exponent associated with the trajectory of the system.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 114-118
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Compound Relaxation Processes in Crystal Lattice Dynamics of Si Irradiated by Soft X-rays
Autorzy:
Janavičius, A. J.
Purlys, R
Norgėla, Ž
Powiązania:
https://bibliotekanauki.pl/articles/2044634.pdf
Data publikacji:
2006-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
61.72.Dd
05.50.+q
Opis:
We applied soft X-rays for investigation of dynamics of Frenkel point defects in a Si crystal during its saturation with metastable vacancies with neighboring Si atoms in excited states or vacancies with neighboring Si atoms in interstitial states produced in the lattice after ejection of Auger electrons. The irradiated irregularities and defects of the lattice cause a change of Bragg reflection maxima. Several resonance phenomena related to the metastable states introduced into Si crystal by soft X-rays irradiation have been detected.
Źródło:
Acta Physica Polonica A; 2006, 109, 2; 159-170
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Behaviors of Phase Diagrams of Ising Model with Competing Ternary and Binary Interactions on a Cayley Tree of Arbitrary Order
Autorzy:
Akin, H.
Ganikhodjaev, N.
Uguz, S.
Temir, S.
Powiązania:
https://bibliotekanauki.pl/articles/1490877.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.De
Opis:
An Ising model with competing interactions has recently been studied extensively because of the appearance of nontrivial magnetic orderings. In this paper, we study the phase diagrams for the Ising model on a Cayley tree with competing nearest-neighbor interactions J and ternary prolonged interactions $J_{t_{p}}$ on a Cayley tree of arbitrary order k and compare with the phase diagrams obtained in Uguz et al. and Vannimenus results for the Ising model on a Cayley tree with competing nearest-neighbor interactions J and ternary prolonged interactions $J_{p}$. For some values of k, we obtain phase diagrams of the model. We clarify the role of order k of the Cayley tree. We also plot the variation of the wave vector with temperature.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 104-107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Lattice and Carriers Hall Mobility Relaxation Processes in Si Crystal Irradiated by Soft X-rays
Autorzy:
Janavičius, A. J.
Storasta, J.
Purlys, R.
Mekys, A.
Balakauskas, S.
Norgėla, Ž.
Powiązania:
https://bibliotekanauki.pl/articles/2047360.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
61.72.Dd
05.50.+q
Opis:
We applied soft X-rays for investigation of dynamics of the Frenkel point defects in a Si crystal during its saturation with metastable vacancies with neighboring Si atoms in excited states produced in the lattice after ejection of the Auger electrons. The irradiated irregularities and defects of the lattice cause a change of the Bragg reflection maxima. Several resonance phenomena are related to metastable states introduced into Si crystal by soft X-rays irradiation. The resonance of mean square displacements of Si atoms in the lattice and the resonance of the Hall mobility after irradiation are obtained and considered.
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 55-68
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rarefied Band in Spectrum of Two-Magnon States of Heisenberg Ferromagnet of Clock Dial Plate
Autorzy:
Lulek, T.
Wal, A.
Powiązania:
https://bibliotekanauki.pl/articles/1933552.pdf
Data publikacji:
1995-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.30.Ds
02.20.-a
75.Jm
Opis:
The Heisenberg isotropic exchange Hamiltonian with the nearest neighbour interactions for the ring of N = 12 nodes (the clock dial plate) with the spin 1/2 has been diagonalized within the manifold of all 66 two-magnon excitations from the ferromagnetic ground state. The spectrum consists of 5 full bands, i.e. bands defined over the whole Brillouin zone, and a single band which is doubly rarefied, i.e. defined only for even values of quasimomentum. The rarefied band is found to be dispersionless outside the centre of the Brillouin zone. It separates two bands of "weakly bounded" spin waves from two other which are "weakly antibounded". The last remaining band is situated below this collection of scattered spin waves, and describes two tightly bounded spin deviations. The spectrum exhibits dispersion, but it is degenerate (singlet and quintet) at the boundary of the Brillouin zone.
Źródło:
Acta Physica Polonica A; 1995, 88, 2; 259-268
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-1 Model of Noninteracting Nanoparticles
Autorzy:
Yalçin, O.
Erdem, R.
Övűnç, S.
Powiązania:
https://bibliotekanauki.pl/articles/1812046.pdf
Data publikacji:
2008-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
75.60.-d
05.50.+q
05.70.Ln
Opis:
In this work, we presented a spin-1 model to investigate the magnetic properties of noninteracting monodomain nanoparticles based on the pair approximation. Nearest-neighbor pair interactions are incorporated between the Ising spins in three parts that are core, core-surface, and surface within the nanoparticle. Using the spin-1 Ising model of magnetization in the pair approximation, we calculated the free energy and minimized with respect to pair variables to obtain the field-cooled magnetization. Hysteresis loops of the system were plotted for various values of exchange coupling constants, and axial anisotropy of strength which couples the core, core-surface, and surface regions. The coercive field and its linear fit to the data were plotted as a function of radius of ferromagnetic nanoparticles.
Źródło:
Acta Physica Polonica A; 2008, 114, 4; 835-844
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced magnetocaloric effect due to selective dilution in a triangular ising antiferromagnet
Autorzy:
Borovský, M.
Žukovič, M.
Powiązania:
https://bibliotekanauki.pl/articles/1054817.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.50.Ee
75.30.Sg
05.10.Ln
Opis:
We employ an effective-field theory with correlations in order to study a magnetocaloric effect on a triangular Ising antiferromagnet, which is selectively diluted by non-magnetic impurities on one of the three sublattices. Such a dilution generally relieves massive degeneracy in our system and therefore the ground-state entropy diminishes and the magnetocaloric effect weakens at low temperatures. However, at relatively higher temperatures we can observe significantly enhanced negative isothermal entropy changes for the sublattice concentration p_A=0.8.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 645-647
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ising Model on Tangled Chain. II. Magnetization and Susceptibility
Autorzy:
Mejdani, R.
Powiązania:
https://bibliotekanauki.pl/articles/1931347.pdf
Data publikacji:
1994-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.50.+m
75.10.Hk
75.10.Nr
05.50.+q
Opis:
In the preceding paper we have considered an Ising model defined on tangled chain to study the behaviour of the free energy and entropy, particularly in the zero-field and zero-temperature limit. In this paper, following the main line and basing on some results of the previous work, we shall study in the "language" of state configurations the behaviour of the magnetization and the susceptibility for different conditions of the model, to understand better the competition between the ferromagnetic bonds along the chain and the antiferromagnetic additional bonds across the chain. Particularly interesting is the behaviour of the susceptibility in the zero-field and zero-temperature limit. Exact solutions for the magnetization and susceptibility, generated by analytical calculations and iterative algorithms, are described. The additional bonds, introduced as a form of perfect disorder, indicate a particular effect on the spin correlation. We found that the condition J = -J' between the ferromagnetic interaction J along the chain and the antiferromagnetic interaction J' across the chain is somewhat as a "transition-region" condition for this behaviour.
Źródło:
Acta Physica Polonica A; 1994, 85, 6; 919-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local Gauge and Magnetic Translation Groups
Autorzy:
Florek, W.
Powiązania:
https://bibliotekanauki.pl/articles/1964708.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
11.15.Ha
05.50.+q
71.45.-d
02.20.-a
Opis:
The magnetic translation group was introduced as a set of operators T(R)=exp[-iR·(p-eA/c)/h]. However, these operators commute with the Hamiltonian for an electron in a periodic potential and a uniform magnetic field if the vector potential A (the gauge) is chosen in a symmetric way. It is showed that a local gauge field A$\text{}_{R}$(r) on a crystal lattice leads to operators, which commute with the Hamiltonian for any (global) gauge field A = A(r). Such choice of the local gauge determines a factor system ω(R,R') = T(R)T(R')T(R+R')$\text{}^{-1}$, which depends on a global gauge only. Moreover, for any potential A a commutator T(R)T(R')T(R)$\text{}^{-1}$T(R')$\text{}^{-1}$ depends only on the magnetic field and not on the gauge.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 399-402
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Kondo Lattice Models and Magnetism for Cerium and Uranium Systems
Autorzy:
Coqblin, B.
Powiązania:
https://bibliotekanauki.pl/articles/1534596.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Mb
75.20.Hr
05.50.+q
64.60.Cn
Opis:
The interplay between the Kondo effect and magnetism is important in anomalous rare-earth and actinide systems and a brief review of the different Kondo lattice models is presented here. The first studied case is the classical Kondo lattice model with S = 1/2 spins for the 4f localized electrons, which describes the strong competition between the Kondo effect and magnetic ordering leading to small ordering temperatures less than roughly 10 K. The second reviewed case describes the underscreened Kondo lattice model with S = 1 spins for the 5f localized electrons, which can account for the coexistence of both the Kondo effect and the ferromagnetic order and, therefore, the large Curie temperatures observed in actinide compounds like UTe and $NpNiSi_2$; the question of the delocalization of the 5f electrons is also discussed here. The last case describes the competition between the "spin glass" behaviour, the Kondo effect and the magnetic ordering in disordered cerium alloys like $CeNi_{x}Cu_{1 - x}$ or $CeRh_{x}Pd_{1 - x}$ and several models used for the spin glass state are reviewed, as well as the occurrence of magnetic glass clusters.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 913-918
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of On-Site Coulomb Repulsion on Phase Transitions in Exactly Solved Spin-Electron Model
Autorzy:
Gálisová, L.
Strečka, J.
Tanaka, A.
Verkholyak, T.
Powiązania:
https://bibliotekanauki.pl/articles/1534796.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.Jk
64.60.Cn
64.60.De
Opis:
A hybrid lattice-statistical model on doubly decorated planar lattices, which have localized Ising spins at their nodal lattice sites and two itinerant electrons at each pair of decorating sites, is exactly solved by the use of a generalized decoration-iteration transformation. Our main attention is focused on an influence of the on-site Coulomb repulsion on ground-state properties and critical behavior of the investigated system.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 942-943
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ising Model on Tangled Chain. I. Free Energy and Entropy
Autorzy:
Mejdani, R.
Powiązania:
https://bibliotekanauki.pl/articles/1931346.pdf
Data publikacji:
1994-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.50.+m
75.10.Hk
75.10.Nr
05.50.+q
Opis:
In this paper we have considered an Ising model defined on tangled chain, in which more bonds have been added to those of pure Ising chain. To understand their competition, particularly between ferromagnetic and antiferromagnetic bonds, we have studied, using the transfer matrix method, some simple analytical calculations and an iterative algorithm, the behaviour of the free energy and entropy, particularly in the zero-field and zero-temperature limit, for different configurations of the ferromagnetic tangled chain and different types of additional interactions (ferromagnetic or antiferromagnetic). We found that the condition J = -J' between the ferromagnetic interaction J along the chain and the antiferromagnetic interaction J' across the chain is somewhat as a "transition region" condition for this behaviour. Our results indicate also the existence of nonzero entropy at zero temperature.
Źródło:
Acta Physica Polonica A; 1994, 85, 6; 907-918
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverse magnetocaloric effect in spin-1/2 Fishers super-exchange antiferromagnet
Autorzy:
Gálisová, L.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1052954.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.30.Et
75.30.Sg
75.30.Kz
Opis:
The isothermal entropy change and the adiabatic temperature change are rigorously calculated for the exactly solved spin-1/2 Fisher's super-exchange antiferromagnet in order to examine magnetocaloric properties of the model in a vicinity of the second-order phase transition. It is shown that the large inverse magnetocaloric effect occurs around the temperature interval T_c(h≠0) < T < T_c(h=0) for any magnetic-field change Δh:0 → h. The most pronounced inverse magnetocaloric effect can be found for the magnetic-field change, which coincides with the critical field of a zero-temperature phase transition from the antiferromagnetically ordered ground state to the paramagnetic one.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 627-629
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Models of Pedestrian Evacuation based on Cellular Automata
Autorzy:
Mrowinski, M.
Gradowski, T.
Kosinski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1409052.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
45.70.Vn
05.50.+q
05.70.Fh
Opis:
We study two models of pedestrian evacuation based on cellular automata and intelligent agents. We use the static floor field approach and augment it with additional transition rules (random movement and preservation of personal space) in order to model various aspects of human behaviour. Through numerical simulations we investigate pedestrian evacuation from rooms with various geometries (e.g. empty room, classroom). Using heatmaps (density diagrams of pedestrians), average evacuation times, velocity and other parameters we study the effectiveness of evacuation and potential dangers pedestrians may encounter.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-95-B-100
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Finite-Size Scaling Study of Five-Dimensional Ising Model
Autorzy:
Merdan, Z.
Aras, N.
Kürkçü, C.
Powiązania:
https://bibliotekanauki.pl/articles/1398913.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.Cn
75.40.Cx
75.40.Mg
Opis:
The five-dimensional ferromagnetic Ising model is simulated on the Creutz cellular automaton algorithm using finite-size lattices with linear dimension 4 ≤ L ≤ 8. The critical temperature value of infinite lattice is found to be $T^{χ}$ (∞=8.7811 (1) using 4 ≤ L ≤ 8 which is also in very good agreement with the precise result. The value of the field critical exponent (δ =3.0067(2)) is good agreement with δ =3 which is obtained from scaling law of Widom. The exponents in the finite-size scaling relations for the magnetic susceptibility and the order parameter at the infinite-lattice critical temperature are computed to be 2.5080 (1), 2.5005 (3) and 1.2501 (1) using 4 ≤ L ≤ 8, respectively, which are in very good agreement with the theoretical predictions of 5/2 and 5/4. The finite-size scaling plots of magnetic susceptibility and the order parameter verify the finite-size scaling relations about the infinite-lattice temperature.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1100-1104
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Hilbert Space and the Exact Solution of the Spin-Electron Double-Tetrahedral Chain
Autorzy:
Jakubczyk, D.
Gálisová, L.
Powiązania:
https://bibliotekanauki.pl/articles/1402563.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.20.-a
05.30.-d
75.10.Pq
05.50.+q
Opis:
We discuss an exactly solvable double-tetrahedral chain, in which the localized Ising spins regularly alternate with triangular clusters - each available for one mobile electron. We give an exact solution for the considered hybrid system by the construction of the N-th tensor power of the Fourier transformation and using the generalized decoration-iteration mapping tranformation.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 173-175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Description of Extreme Gibbs Measures for the Ising Model with Three Interactions
Autorzy:
Akin, H.
Ganikhodjaev, N.
Temir, S.
Uguz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1400048.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.De
75.10.Hk
Opis:
In this paper, we consider an Ising model with three competing interactions (nearest neighbor, next-nearest neighbor, and ternary prolonged neighbor) on the Cayley tree of order two, investigated by Ganikhodjaev et al. We study translation-invariant Gibbs measures of the Ising model with these competing interactions. Also, we investigate the set of the extreme Gibbs measures called Markov random fields with memory 2 of the model.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 484-487
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Temperature Properties of Ising Antiferromagnet on a Stacked Triangular Lattice
Autorzy:
Žukovič, M.
Mižišin, L.
Bobák, A.
Powiązania:
https://bibliotekanauki.pl/articles/1199547.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.De
75.10.Hk
75.50.Ee
Opis:
An Ising antiferromagnet on a stacked triangular lattice in zero field is studied by Monte Carlo simulations, focusing on the character of the low-temperature phase and the effect of the relative strength of the exchange interaction in the stacking direction α. Our results support the presence of the 3D Wannier phase, with the sublattice magnetization structure (m, -m, 0) and power-law decaying m with the lattice size. The extent of this low-temperature phase shrinks with decreasing α, however, it appears even at very low values if it is accessed from higher temperatures by sufficiently slow cooling.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 40-41
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Gibbs Measures of the Potts Model with Three Competing Interactions on Cayley Tree of Order 3
Autorzy:
Akin, H.
Saygılı, H.
Powiązania:
https://bibliotekanauki.pl/articles/1186977.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
75.10.Hk
64.60.De
Opis:
In this paper, we consider the Potts model with competing interactions on the Cayley tree of order three. We give the Potts model on the Cayley tree and its recursion relation. We construct the Gibbs states corresponding to the model by using Markov random field method. We calculate the critical curve, such that there is a phase transition for the model. We show that there are phase transition of the model for some given parameters. We extend the results obtained by Akin and Temir (Condensed Matt. Phys. 14, 23003 (2011)).
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 845-848
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Dimensional Ising Model with Competing Interactions as a Model for Interacting π-Rings
Autorzy:
O'Hare, A.
Kusmartsev, F.
Kugel, K.
Powiązania:
https://bibliotekanauki.pl/articles/1810411.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Hk
74.81.Fa
03.67.Lx
Opis:
We investigate the Ising model on a square lattice with antiferromagnetic exchange between nearest and next-nearest neighbors and show that at low temperatures stripe-like and droplet-like superstructures appear. We show that the competing interactions introduce a strong frustration that could plausibly describe the systems with dipole-dipole type interactions and pay particular attention to arrays of interacting Josephson π-rings.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 150-152
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetism and Kondo Effect in Cerium and Uranium Compounds
Autorzy:
Coqblin, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813756.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Hr
75.30.Mb
05.50.+q
64.60.Cn
Opis:
A brief review of the Kondo lattice problem is presented, with a special emphasis on the underscreened Kondo effect in ferromagnetic-Kondo uranium compounds and on the spin glass-Kondo competition in disordered heavy fermion cerium alloys.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 391-394
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetization and Susceptibility of a Diluted Triangular Ising Antiferromagnet in a Field
Autorzy:
Borovský, M.
Žukovič, M.
Bobák, A.
Powiązania:
https://bibliotekanauki.pl/articles/1199489.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.De
75.10.Hk
75.50.Ee
Opis:
Within the framework of the effective-field theory with correlations we investigate effects of an external magnetic field and random site dilution on basic thermodynamic quantities, such as the magnetization and the magnetic susceptibility, on the geometrically frustrated triangular lattice Ising antiferromagnet. Behavior of these quantities is presented in the temperature-field parameter space for selected mild degrees of dilution. It is found that, besides the anomalies associated with phase transitions from the ferrimagnetic to the paramagnetic state, in certain regions of the parameter space these functions display some more anomalies and peculiarities, as a result of joint effects of the geometrical frustration, magnetic dilution, thermal fluctuations and the applied magnetic field.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 16-17
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact Ground States of Frustrated Spin-1 Ising-Heisenberg and Heisenberg Ladders in a Magnetic Field
Autorzy:
Strečka, J.
Michaud, F.
Mila, F.
Powiązania:
https://bibliotekanauki.pl/articles/1199503.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Jm
75.10.Kt
75.60.Ej
Opis:
Ground states of the frustrated spin-1 Ising-Heisenberg two-leg ladder with Heisenberg intra-rung coupling and only Ising interaction along legs and diagonals are rigorously found by taking advantage of local conservation of the total spin on each rung. The constructed ground-state phase diagram of the frustrated spin-1 Ising-Heisenberg ladder is then compared with the analogous phase diagram of the fully quantum spin-1 Heisenberg two-leg ladder obtained by density matrix renormalization group (DMRG) calculations. Both investigated spin models exhibit quite similar magnetization scenarios, which involve intermediate plateaux at one-quarter, one-half and three-quarters of the saturation magnetization.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 24-25
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Orientational Ordering for System of Ellipsoidal Molecules Dispersed in Cubic Lattice
Autorzy:
Mejdani, R.
Powiązania:
https://bibliotekanauki.pl/articles/1952744.pdf
Data publikacji:
1996-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.Cn
64.60.My
64.70.Md
Opis:
We represent here some results for a model of migrating and nonmigrating ellipsoidal molecules dispersed in a cubic lattice, describing: the orientational ordering in nematics, the possibility of a biaxial ordered liquid state, the orientational ordering in solid hydrogen (orto-H$\text{}_{2}$ or para-D$\text{}_{2}$) or the orientational glassy structure (the "higher rank"glass state). Through this kind of molecular ensemble (in the case of the system of ellipsoidal and spherical molecules) it is also possible to study the orientational and positional orderings in binary mixtures and to obtain the so-called plastic state.
Źródło:
Acta Physica Polonica A; 1996, 90, 6; 1127-1141
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spontaneous Magnetization and Phase Diagrams of the Mixed Spin-1/2 and Spin-S Ising Model on the Bethe Lattice
Autorzy:
Strečka, J.
Ekiz, C.
Powiązania:
https://bibliotekanauki.pl/articles/1032659.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.10.Hk
75.10.Kz
75.40.Cx
Opis:
The effect of uniaxial single-ion anisotropy on magnetic and critical properties of the mixed spin-1/2 and spin-S (S>1/2) Ising model on a three-coordinated Bethe lattice is rigorously examined with the help of star-triangle transformation and exact recursion relations. In particular, our attention is focused on the ferrimagnetic version of the model, which exhibits diverse temperature dependences of the total and both sublattice magnetizations. It is shown that the critical behavior of the mixed-spin Ising model on the Bethe lattice basically depends on whether the quantum spin number S is integer or half-odd-integer.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 615-617
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rise and Fall of Reentrant Phase Transitions in a Coupled Spin-Electron Model on a Doubly Decorated Honeycomb Lattice
Autorzy:
Čenčariková, H.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032648.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.Fh
71.27.+a
75.30.Kz
Opis:
Phase diagrams and spontaneous magnetization are rigorously calculated for a coupled spin-electron model on a doubly decorated honeycomb lattice, which accounts for a quantum-mechanical hopping of the mobile electrons on decorating sites, the nearest-neighbor Ising coupling between mobile electrons and localized spins, as well as the further-neighbor Ising coupling between the localized spins placed on nodal sites. The spontaneously ordered ferromagnetic phase, spontaneously ordered antiferromagnetic phase and disordered paramagnetic phase emerge in a phase diagram depending on an electron filling of the decorating sites, a relative size of the hopping term and both considered coupling constants. It is evidenced that a nature and size of the further-neighbor Ising coupling between the localized spins basically influences rise and fall of reentrant transitions close to a phase boundary between the paramagnetic phase and both spontaneously ordered phases.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1021-1023
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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