Abstract
Thermal-assisted magnetization time decay for most magnetic recording media exhibits nonlinear behavior against logarithmic time scale, when a long-term(for example 24-hour)measurement is performed. On the basis of measured date for MP and Ba ferrite tapes, the temporal change of magnetization viscosity was approximated by two kinds of distribution function. For Ba ferrite tape, which exhibited the most distinct non-linear magnetization time decay, time constants distributed from 50 to 10^5 sec for the uniform distribution, and the mean-time=5000 sec with standard deviation time=200 sec for the log-normal distribution were obtained.
