scholarly journals Ferromagnetic and spin-glass like transition in the q-neighbor Ising model on random graphs

2021 ◽  
Vol 94 (3) ◽  
Author(s):  
A. Krawiecki
Keyword(s):  
Monte Carlo ◽  
Ising Model ◽  
Monte Carlo Simulations ◽  
Spin Glass ◽  
Phase Diagrams ◽  
Random Graphs ◽  
Second Order ◽  
Ferromagnetic Phase ◽  
Ferromagnetic Transition ◽  
Antiferromagnetic Exchange

Abstract The q-neighbor Ising model is investigated on homogeneous random graphs with a fraction of edges associated randomly with antiferromagnetic exchange integrals and the remaining edges with ferromagnetic ones. It is a nonequilibrium model for the opinion formation in which the agents, represented by two-state spins, change their opinions according to a Metropolis-like algorithm taking into account interactions with only a randomly chosen subset of their q neighbors. Depending on the model parameters in Monte Carlo simulations, phase diagrams are observed with first-order ferromagnetic transition, both first- and second-order ferromagnetic transitions and second-order ferromagnetic and spin-glass-like transitions as the temperature and fraction of antiferromagnetic exchange integrals are varied; in the latter case, the obtained phase diagrams qualitatively resemble those for the dilute spin-glass model. Homogeneous mean-field and pair approximations are extended to take into account the effect of the antiferromagnetic exchange interactions on the ferromagnetic phase transition in the model. For a broad range of parameters, critical temperatures for the first- or second-order ferromagnetic transition predicted by the homogeneous pair approximation show quantitative agreement with those obtained from Monte Carlo simulations; significant differences occur mainly in the vicinity of the tricritical point in which the critical lines for the second-order ferromagnetic and spin-glass-like transitions meet. Graphic abstract

Monte Carlo Simulations of Spin Glass Systems on the Cell Broadband Engine

2010 ◽  
pp. 467-476 ◽  
Author(s):  
Francesco Belletti ◽  
Marco Guidetti ◽  
Andrea Maiorano ◽  
Filippo Mantovani ◽  
Sebastiano Fabio Schifano ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Spin Glass ◽  
Cell Broadband Engine

The Relation Between Defects and Relaxation in Viscous Liquids

1985 ◽  
Vol 61 ◽  
Author(s):  
S. Brawer
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Ising Model ◽  
Monte Carlo Simulations ◽  
Relaxation Behavior ◽  
Atomic Diffusion ◽  
Kinetic Ising Model ◽  
Viscous Liquids ◽  
First Approximation

ABSTRACTIt is shown that defects can be identified in liquids, that they are related to atomic diffusion, and a model is described whereby defects give rise to the observed relaxation behavior of viscous liquids. A review is presented of defects in silicate and fluoroberyllate liquids, as studied by computer simulation. It is found that defects have the form of overcoordinated or undercoordinated atoms, and that atomic diffusion occurs only at the site of defects. The manner in which an Ising model can represent the detect structure of viscous liquids to a first approximation is presented. The results of Monte Carlo simulations of a 2-dimensional kinetic Ising model are described. The behavior of this model is qualitatively the same as that of viscous liquids.

Magnetic Properties Study of the Nano-Alloy Fe1+xCo1−x by Monte-Carlo Simulations

SPIN ◽  
2019 ◽  
Vol 09 (01) ◽  
pp. 1950002 ◽  
Author(s):  
I. El Housni ◽  
H. Labrim ◽  
N. El Mekkaoui ◽  
S. Idrissi ◽  
R. Khalladi ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Magnetic Properties ◽  
Monte Carlo Simulations ◽  
Phase Diagrams ◽  
Ground State ◽  
Exchange Coupling ◽  
Hysteresis Loops ◽  
Metropolis Algorithm ◽  
Spintronic Devices ◽  
Temperature Exchange

Motivated by spintronic devices and their applications, we engineer a model to investigate the magnetic properties of the magnetic nano-alloy Fe[Formula: see text]Co[Formula: see text]. Where [Formula: see text] is the fraction of iron atoms Fe substituted by the cobalt Co atoms, [Formula: see text] corresponds to 50% Fe atoms and 50% Co atoms, this compound is then called equiatomic FeCo. The purpose of this work is to apply the Monte-Carlo Simulations (MCS), under Metropolis algorithm to predict the magnetic properties of such system. In a first step, we propose a model describing this system including different exchange coupling interactions. Then, we establish and analyze the ground state phase diagrams, in different planes. For non-null temperature values, applied MCS under the Metropolis algorithm. The behavior of both the magnetizations and the susceptibilities are illustrated as a function of temperature. Also the effect of the different exchange coupling interactions is studied and discussed. The hysteresis loops are presented and analyzed for specific values of temperature, exchange coupling interactions and concentrations.

scholarly journals MONTE CARLO SIMULATION OF ISING MODEL ON DIRECTED BARABASI–ALBERT NETWORK

2005 ◽  
Vol 16 (04) ◽  
pp. 585-589 ◽  
Author(s):  
MUNEER A. SUMOUR ◽  
M. M. SHABAT
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Ising Model ◽  
Monte Carlo Simulations ◽  
Characteristic Time ◽  
Spontaneous Magnetization ◽  
Zero Temperature ◽  
Different Temperatures ◽  
Large Systems ◽  
Ising Spins

The existence of spontaneous magnetization of Ising spins on directed Barabasi–Albert networks is investigated with seven neighbors, by using Monte Carlo simulations. In large systems, we see the magnetization for different temperatures T to decay after a characteristic time τ(T), which is extrapolated to diverge at zero temperature.

Phase diagrams of the spin-1 Ising Blume-Emery-Griffiths model: Monte Carlo simulations

1987 ◽  
Vol 36 (16) ◽  
pp. 8945-8947 ◽  
Author(s):  
Yung-Li Wang ◽  
Felix Lee ◽  
J. D. Kimel
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Phase Diagrams
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