Inhomogeneities and coercivity of soft Permalloy thin films

Coercivity mechanisms in thin 1000-AA Permalloy films due to inhomogeneous distributions of in-plane uniaxial anisotropy are investigated numerically, utilizing a two-dimensional domain wall model. The distribution of anisotropy could be attributed to the polycrystalline grain structure of thin films, as well as magnetostrictive stress. Typical anisotropy orientation dispersion induced by polycrystalline grains does not appear to account for the wall coercive force observed in soft Permalloy films. Other mechanisms, such as stress-induced anisotropy, may be dominant.<
>