COERCIVITY OF ULTRATHIN FILMS WITH INPLANE MAGNETIZATION

We report numerical and analytic results for a model of coercivity and magnetization reversal in an array of square monolayer-height magneti c islands on a monolayer of magnetic material with in-plane magnetizat ion. Reversal nucleates at step edges where local two-fold anisotropy is present in addition to the intrinsic four-fold anisotropy of the (0 01) flat surface of a cubic crystal. Simple analytic formulas for the coercive field are derived that agree well with numerical simulations. (C) 1997 American Institute of Physics.