scholarly journals Assembly-mediated interplay of dipolar interactions and surface spin disorder in colloidal maghemite nanoclusters

Nanoscale ◽  
2014 ◽  
Vol 6 (7) ◽  
pp. 3764-3776 ◽  
Author(s):  
A. Kostopoulou ◽  
K. Brintakis ◽  
M. Vasilakaki ◽  
K. N. Trohidou ◽  
A. P. Douvalis ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Spin Glass ◽  
Volume Fraction ◽  
Colloidal Nanoparticles ◽  
Dipolar Interactions ◽  
Spin Disorder ◽  
Dynamical Susceptibility ◽  
Glass Dynamics ◽  
Surface Spin

Dynamical susceptibility and Monte Carlo simulations unravel the spin-glass dynamics due to the assembly of colloidal nanoparticles in clusters with increased volume fraction.

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

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

scholarly journals Monte Carlo simulations of a kagome lattice with magnetic dipolar interactions

2015 ◽  
Vol 91 (22) ◽  
Author(s):  
M. S. Holden ◽  
M. L. Plumer ◽  
I. Saika-Voivod ◽  
B. W. Southern
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Dipolar Interactions ◽  
Kagome Lattice ◽  
Kagomé Lattice

On the Recrystallization Kinetics of 3D Potts Monte Carlo Simulations

2012 ◽  
Vol 715-716 ◽  
pp. 959-964
Author(s):  
E. Fjeldberg ◽  
Knut Marthinsen
Keyword(s):  
Monte Carlo ◽  
Time Delay ◽  
Monte Carlo Simulations ◽  
Volume Fraction ◽  
Avrami Exponent ◽  
Initial Transient ◽  
Recrystallization Kinetics ◽  
Start Up ◽  
Kinetics Of

The present simulations have clearly demonstrated that the kinetics, as derived directly from the 3D Potts Monte Carlo simulations, deviate strongly from the classical JMAK theory. The Avrami plots exhibit a strong initial transient and the Avrami exponents are far from constant and generally much lower than predicted by the classical JMAK theory. However, by introducing a suitable time delay,t0, due to a non-zero volume fraction of recrystallized grains at the start-up of the simulations, this initial transient can be removed and the Avrami plots are made close to linear at the same time as the Avrami exponent is in better agreement with theory.

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