Phase Diagram of a Short-Range ±<i>J</i>Heisenberg Modelin Three Dimensions

Abstract

The short-range ± J Heisenberg model with the concentration of ferromagnetic bonds p on a simple cubic lattice is studied using a hybrid Monte-Carlo spin-dynamics (HMCSD) method. Using a finite-size scaling analysis, we find the critical concentration of p c =0.79±0.01 and the ferromagnetic phase transition for p > p c which belongs to the same universality class as that of the pure ferromagnet. We also find that no random spin freezing occurs in our model.