Magnetostriction and soft magnetic properties of (Co1−xFex)–Al–O granular films with high electrical resistivity

Abstract

We have investigated the magnetic properties of (Co1−xFex)–Al–O granular thin films prepared by a reactive sputtering method in an atmosphere of O2+Ar. The coercivity and electrical resistivity of the films are almost independent of x, but with increasing x the anisotropy field decreases linearly and the saturation induction has a broad maximum of 20 kG around x=0.7. The granular films show the same general tendency as bulk Co–Fe alloys in the compositional dependence of magnetostriction (λ). The magnitude of λ varies with increasing annealing temperature. Using a film with x=0.08 as the core of a spiral-wound inductor gave a quality factor Q=25 at a frequency of 300 MHz.