Spin-glass ordering in diluted magnetic semiconductors: A Monte Carlo study

Abstract

We study the temperature-dilution phase diagram of a site-diluted Heisenberg antiferromagnet on a facecertered-cubic lattice, with and without the Dzyaloshinskii-Moriya anisotropic term, fixed to realistic microscopic parameters for IIB_(1-x)Mn_(x)Te(IIB=Cd,Hg,Zn). We show that the dipolar Dzyaloshinskii-Moriya anisotropy induces a finite-temperature phase transition to a spin-glass phase, at dilutions larger than 80%. The resulting probability distribution of the order parameter P(q) is similar to the one found in the cubic lattice Edwards-Anderson-Ising model. The critical exponents undergo large finite-size corrections, but tend to values similar to the ones of the Edwards-Anderson-Ising model.