Statistical approach based on the Stoner-Wohlfarth model for the switching field in a misoriented magnet array

Stoner‒Wohlfarth model (S‒W model) is used to explain the relationship between the external magnetic field and the magnetization reversal of a single magnetic domain. However, it is inappropriate for inhomogeneous magnetic films or bulk materials, such as granular and defective films, because the magnetization reversal of the films is affected by magnetic particles or grains which could have a different anisotropy for uniaxial magnetic anisotropy (UMA) of the films. In this paper, we propose a model based on the S‒W model to understand the magnetization switching behavior of magnetic films with misoriented grains. Our model considers the distribution effect of different anisotropies originating from magnetic defects or domains against the UMA of a magnetic thin film, and a Gaussian function is employed for the probability distribution of tilted anisotropy. Finally, we experimentally demonstrate that our model describes the magnetic switching behavior of a granular magnetic film (FePt-C) with perpendicular magnetic anisotropy. This study provides a new analytical method for the magnetization reversal in magnetic devices.