SPIN FREEZING PROPERTIES OF AN ISING SPIN-GLASS FE0.05TIS2 IN ZERO AND NONZERO MAGNETIC-FIELDS

In order to understand spin freezing properties, ac-susceptibility chi(ac) and relaxation of thermoremanent magnetization (TRM) were measured on an Ising spin glass Fe0.05TiS2 in zero and non-zero fields. Analysis of chi(ac) above the spin glass freezing temperature shows that a rectangular distribution of spin relaxation times is appropriate and the temperature dependence of the average spin relaxation time follows the power law. The waiting time effects on the relaxation of TRM below the freezing temperature can be interpreted by a hierarchical many-valley structure. These results are consistent with Sherrington-Kirkpatrick model's prediction that the spin glass freezing is a phase transition in both zero and non-zero fields.