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

We have investigated the magnetic properties of (Co1-xFex)-Al-O granular thin films prepared by a reactive sputtering method in an atmosphere of O-2 + 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 (lambda). The magnitude of lambda 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. (C) 1999 American Institute of Physics. [S0021-8979(99)53108-3].