Monte-Carlo simulations of a random-field Ising-O(3) model

Many of the iron-based superconducting compounds undergo a structural phase transition and stabilize a stripe-like spin-order at low temperatures. We investigate the relation between the structural and magnetic phase transitions in these materials and study the effects of random strain commonly found in the samples.
To do so, the magnetic properties of these materials are modeled via quasi-two dimensional Ising-0(3) model which describes both spin and nematic (stripe) degrees of freedom. Random strain is included via a random field term coupling to the nematic variables. We perform large-scale Monte Carlo simulations of this model to determine the phase diagram and characterize the phase transitions.