Switching field time dependence of thin film media

The dependence of remanent coercivity of thin film media on pulse duration has been measured for time intervals from 1.4 ns to 270 hr, The apparatus c ombines the field from a micro conductor with that of a DC magnet to switch the media, The data from 54 ns to 270 hr fits well to Sharrock's Law with an exponent of 0,716, The data for times less than 8 ns indicate weak gyro- magnetic enhancement of the switching field. Micromagnetic simulation shows that this can be explained by either magnetostatic or exchange coupling be tween the grains.