Abstract

A model that describes the behavior of the coercivity Hc, of coalescing Ni films, as a percolation phenomenon is presented. We show that there is a nonmonotonic dependence, of the coercive field as a function of the occupation probability p. This behavior is a function of cluster size and topology, and is independent of the growth direction of the thin film. Based on these ideas we predict theoretically, and confirm experimentally, the dependence of Hc as a function of external magnetic field orientation. For a [111] oriented fcc film, if p is less than the percolation threshold Pcr, a sixfold symmetry is observed. However, if p ? Pcr the percolation is isotropic.