Ivaneiko D. Analysis of the influence of structural disorder and frustrations on the critical behavior of three-dimensional magnets

The critical behavior of 3D Ising model with two types of structural disorder and 3D model of the stacked triangular antiferromagnet was investigated. Monte Carlo simulations (Metropolis, Swendsen-Wang and Wolff algorithms) and the methods of analysis of renormalization group expansions (pseudo-? expansion, resummation of asymptotic series) were applied. Characteristics of static and dynamic critical behavior of the Ising model with non-correlated and with long-range correlated disorder: values of the static critical exponents, universal amplitude ratios, critical temperatures, autocorrelation times, values of the dynamical critical exponents for algorithms were obtained. For the stacked triangular antiferromagnet was obtained the pseudo-? expansions for marginal dimensions in six-loops approximation and defined the order of the phase transition in this model.