Monte Carlo simulations concerning zero field host NMR in aCuMn spin glass

1986 ◽  
Vol 62 (4) ◽  
pp. 463-471 ◽  
Author(s):  
C. Tempelmann ◽  
H. Br�mer
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Spin Glass ◽  
Zero Field

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 Memory and superposition in a superspin glass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
D. Peddis ◽  
K. N. Trohidou ◽  
M. Vasilakaki ◽  
G. Margaris ◽  
M. Bellusci ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Spin Glasses ◽  
Ac Susceptibility ◽  
Exchange Interactions ◽  
Zero Field ◽  
Interparticle Interactions ◽  
Surface Exchange ◽  
Atomic Spin ◽  
Superspin Glass

AbstractThe non-equilibrium dynamics of the superspin glass state of a dense assembly of ~ 2 nm MnFe2O4 nanoparticles was investigated by means of magnetization, ac susceptibility and Mössbauer spectroscopy measurements and compared to the results of Monte Carlo simulations for a mesoscopic model that includes particles morphology and interparticle interactions. The zero-field cooled (ZFC), thermoremanent (TRM), and isothermal remanent magnetization (IRM) were recorded after specific cooling protocols and compared to those of archetypal spin glasses and their dimensionality. The system is found to display glassy magnetic features. We illustrate in detail, by a number of experiments, the dynamical properties of the low-temperature superspin glass phase. We observe that these glassy features are quite similar to those of atomic spin glasses. Some differences are observed, and interestingly, the non-atomic nature of the superspin glass is also reflected by an observed superspin dimensionality crossover. Monte Carlo simulations—that explicitly take into account core and surface contributions to the magnetic properties of these ultrasmall nanoparticles in direct contact, as well as interparticle interactions—evidence effects of the interplay between (intraparticle) core/surface exchange coupling and (interparticle) dipolar and exchange interactions.

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.

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