Phase transitions in a three-dimensional partially disordered and frustrated Ising crystal

Abstract

The authors investigate, by Monte Carlo simulations, the physical properties of a three-dimensional Ising crystal which is partially frustrated due to disorder in the distribution of the bonds of strength+or-J. They calculate, as a function of the bond disorder, the Edwards-Anderson order parameter, the internal energy and the spatial correlation functions with varying temperature. When the disorder is small, there is a transition from the paramagnetic state to an antiferromagnetic state. As the disorder increases, they find evidence of successive phase transitions with decreasing temperature: transitions from the paramagnetic state to an antiferromagnetic state and then to a re-entrant spin-glass state. When disorder becomes very important there is only a transition from the paramagnetic state to a spin-glass state. The different behaviours of spatial correlation functions in these phases are shown and discussed. A general phase diagram is conjectured.