Relaxation and aging in Ising systems.

Abstract

A sequential relaxation model for the susceptibility of site diluted Ising systems is introduced. Most of the necessary parameters are known for the two-dimensional Ising spin glass ${\mathrm{Fe}}_{0.4}$ ${\mathrm{Mg}}_{0.6}$ ${\mathrm{Cl}}_{2}$ and a good fit to experimental results for the ac susceptibility is obtained. Predictions of the model yield good agreement with aging experiments on ${\mathrm{Rb}}_{2}$${\mathrm{Cu}}_{0.89}$${\mathrm{Co}}_{0.11}$${\mathrm{F}}_{4}$ and ${\mathrm{Fe}}_{0.5}$${\mathrm{Mn}}_{0.5}$ ${\mathrm{TiO}}_{3}$. \textcopyright{} 1996 The American Physical Society.