RELAXATION OF THE EXCESS MAGNETIZATION OF RANDOM-FIELD-INDUCED METASTABLE DOMAINS IN FE0.47ZN0.53F2

The Faraday rotation of the excess magnetization in the field-cooled random-field Ising antiferromagnet Fe0.47Zn0.53F2 has been measured for fields 0 < H < 7 T applied along the easy axis at temperatures 5 K < T < 22 K, well below the H = 0 phase transition occurring at T = T(N) (= 37 K). The relaxation of the excess magnetization, which is proportional to the Faraday rotation, does not follow the Nattermann-Vilfan theory in detail for this range of T and H. We explore other possible forms for the time dependence of the excess magnetization and use Monte Carlo techniques as an aid in the interpretation of the experimental data.