Magnetic Properties of Polycrystalline and Amorphous Cobalt- and Nickel-Ferrite Films

The magnetic properties of polycrystalline and amorphous cobalt- and nickel-ferrite films obtained by solid-phase synthesis are studied. Polycrystalline nickel-ferrite films are shown to be characterized by significant coercive fields at room temperature in the direction normal to the substrate plane. Compressive stresses that arise in the films during solid-phase oxidation and synthesis are assumed to contribute to the enhancement of the coercive fields. In polycrystalline films, a magnetic anisotropy of the easy plane type, characteristic of two-dimensional layers, is found. X-ray amorphous films have only paramagnetic properties.