Eur. Phys. J. B (2015) 88: 81
https://doi.org/10.1140/epjb/e2015-50604-x

Regular Article

Ordered vs. disordered states of the random-field model in three dimensions

Physics Department, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, 10468-1589 New York, USA

^a e-mail: einschlag@gmail.com

Received: 5 September 2014
Received in final form: 13 February 2015
Published online: 1 April 2015

Abstract

We report numerical investigation of the glassy behavior of random-field exchange models in three dimensions. Correlation of energy with the magnetization for different numbers of spin components has been studied. There is a profound difference between the models with two and three spin components with respect to the stability of the magnetized state due to the different kinds of singularities: vortex loops and hedgehogs, respectively. Memory effects pertinent to such states have been investigated. Insight into the mechanism of the large-scale disordering is provided by numerically implementing the Imry-Ma argument in which the spins follow the random field averaged over correlated volumes. Thermal stability of the magnetized states is investigated by the Monte Carlo method.