Single-domain crystal-anisotropy-dominated coercivity.

Abstract

We present a theoretical approach to the problem associated with the anomalous coercivity observed in granular magnetic solids such as iron or cobalt embedded in an insulating medium and to amorphous multilayer thin films. In this paper we show that if the magnetic moments at the granular surface or multilayer interface are pinned, such enhanced coercivity is predictable. The model used assumes a one-dimensional dependence of the magnetization (along the length of the granule or the depth of the layer). That dimension is taken to be small to inhibit the appearance of domain walls parallel to that direction. We consider materials whose energy is dominated by a Zeeman term, an anisotropy term, a demagnetization term, and an exchange term