RELAXATION OF THE REMANENT MAGNETIZATION OF DILUTE ANISOTROPIC ANTIFERROMAGNETS

The relaxation of the remanent magnetization of metastable domains in field-cooled, dilute antiferromagnets is studied with use of Monte Carlo simulations. The relaxation is extremely slow due to strong pinning by magnetic vacancies, as previously observed. The function M(tau)(t)=M0exp{- A[ln(t/t')]y}, suggested by results of recent experiments on Fe0.47Zn0.53 F2, is used to fit the simulation data and yields excellent fits with a greater than unity value for y, consistent with the experimental results. This form appears to fit the simulation data much better than either of the functions proposed earlier, namely the power law M(tau)(t) = M0t(x) and the equation M(r)(t) = A[ln(t/t0)]-psi, where psi almost-equal-to 0.4.