Origin of the universality of long-time thermal relaxations in hysteretic systems

It is demonstrated that asymptotic temporal behavior of thermal noise is re sponsible for the universality of long-time thermal relaxations in hysteret ic systems. By using the Preisach hysteresis model and by assuming stationa ry Gaussian noise, the root ln t intermediate asymptotics for the thermal r elaxations is derived along with a simple expression for the viscosity coef ficient in terms of temperature and differential susceptibility. Experiment al data supporting these analytical results are presented. (C) 2000 America n Institute of Physics. [S0021-8979(00)15408-8].