Effect of stress on the shape of ferromagnetic hysteresis loops

The shape of ferromagnetic hysteresis loops is described in terms of symmetric Brown and antisymmetric Bozorth stress fields. The magnetization and nonlinear stress dependence of stress fields are measured and plotted. The Brown field is found to exist in every magnetoelastic process and is manifested when hysteresis of 90 degrees domain walls is asymmetric. Stress fields are derived from magnetoelastic energy density both within a ferromagnetic grain and throughout the sample and are a measure of domain structure. The common stress crossover of saturate curves is modeled in terms of fraction of 90 degrees domain walls. The Brown stress field changes the coercive field and the Bozorth stress field changes remanence.