INTEGRAL RELAXATION-TIME OF SINGLE-DOMAIN FERROMAGNETIC PARTICLES

The integral relaxation time tau(int) of thermoactivating noninteracti ng single-domain ferromagnetic particles is calculated analytically in the geometry with a magnetic field H applied parallel to the easy axi s. It is shown that the drastic deviation of tau(int)(-1) from the low est eigenvalue of the Fokker-Planck equation Lambda(1) at low temperat ures, starting from some critical value of H, is the consequence of th e depletion of the upper potential well. In these conditions the integ ral relaxation time consists of two competing contributions correspond ing to the overbarrier and intrawell relaxation processes.