Rotational hysteresis model for stressed ferromagnetic films

The effect of an external mechanical stress on the coercive force of Ni is different for bulk and for thin films. The bulk behavior is correctly explained by the Sablik-Jiles model which assumes that wall displacement is the driving mechanism of the magnetization process. In thin films, on the other hand, magnetization rotation might be a relevant mechanism, and this could explain the experimental differences with respect to bulk. In order to verify the correctness of this assumption, we constructed another model which was based on magnetization rotation. This new model is based on the bidimensional Stoner-Wohlfarth model, with additional terms which account for magnetostrictive energy and interactions among grains. Its predictions about coercive force behavior and general cycle shape are compared with experimental data on electroplated and evaporated Ni films with thicknesses from 15 to 200 nm.