Monte Carlo studies of slow relaxation in diluted antiferromagnets

Monte Carlo simulations of diluted Ising-type antiferromagnets in a uniform external magnetic field in three dimensions show rather strong irreversibilities in the magnetization and a slow relaxation of the remanent magnetization of the domain state. A detailed investigation of the domain state and its relaxation shows that for low temperatures domains are strongly pinned at vacancies and that relaxation primarily takes place in the domain walls.