A Soft Solution Processing Technique for Preparing Ferrite Films and Their Applications

Abstract

“Ferrite plating” is a typical “soft solution processing” (SSP) application; it enables the formation of oxide ferromagnetic films from an aqueous solution atT24−100°C under atmospheric pressure. Using ferrite plating, we can grow crystallized ferrite films of spinel-type (MFe)3O4(where M = Fe, Co, Ni, Zn, Al, Cr, etc.) in one step, requiring no heat treatment. This opens the door to fabricating novel ferritefilm devices using substrates of such nonheat-resistant materials as plastics and GaAs integrated circuits; conventional ferrite-film preparation techniques, such as sputtering, vacuum evaporation, molecularbeam epitaxy, liquid-phase epitaxy, and so on, require high temperatures (>∼600°C) for the crystallization of ferrites, which deteriorates the non-heat-resistant substrates. Ferrite plating is a unique technique that allows us to synthesize ferrite “films” by means of a wet chemical process. There are many techniques, for synthesizing ferrite “particles” from aqueous solutions, but no technique, to our knowledge, enables ferrite-film synthesis by a wet chemical process.