A Simulation of Rotational Hysteresis Energy Loss in Longitudinal Thin-Film Media

Abstract

AbstractThe field dependence of the rotational hysteresis energy loss was simulated for longitudinal thin-film media with the purpose of examining the validity of this method for measuring the anisotropy field. The field at which the rotational hysteresis vanishes, which is usually taken as the experimentally measured anisotropy field, was found to be smaller than the real anisotropy field when intergranular magnetostatic and exchange interactions are included in the simulations. Hence the rotational hysteresis method may result in an underestimation of the anisotropy field for the films with non-negligible grain interactions. To confirm this experimentally, two CoCrTa films, one with strong in-plane easy axis texture and the other with uniaxially aligned grain easy axes, were prepared under the same conditions. The anisotropy field determined by the rotational hysteresis of the first sample was found to be smaller than the more accurate value obtained from the hard axis hysteresis loop of the second sample.