Preparation of Zinc- and Aluminum-Substituted Cobalt-Ferrite Thin Films and Their Faraday Rotation

Abstract

Zinc- and aluminum-substituted cobalt-ferrite thin films were prepared on fused quartz substrates using vacuum evaporation followed by heat treatment. Magnetic measurements and X-ray diffraction analyses of the films showed that zinc and aluminum were successfully substituted in the spinel lattice and that the Curie temperature was reduced by both substitutions. The Faraday rotation spectra of the films were measured and the difference between Co-ferrite, CoZn-ferrite- and CoAl-ferrite films are discussed considering the distribution of Co²⁺ and Fe³⁺ over the lattice sites and the difference of the lattice constants. The performance factor of the films was improved around 800 nm by zinc substitution and around 1500 nm by aluminum substitution.