Preparation and Characterization of NiZn Ferrite Thin Films by a Spray Pyrolysis Deposition Method

Nickel-zinc (NiZn) ferrite thin films were successfully prepared from nickel, zinc, and iron nitrates aqueous solutions at a substrate temperature between 350 and 500°C in air by a spray pyrolysis deposition method (SPD), where the film thickness was held at about 1μm and the deposition rate was varied between 100 and 200nm/min depending on the substrate temperature. The crystallinity of as-prepared NiZn ferrite films became higher with increasing substrate temperature, but it could not reach a suitable value to produce magnetic properties suitable for practical applications. It was then necessary to anneal the films at higher temperatures above 600°C. Magnetic properties comparable with those of bulk NiZn ferrite and applicable to practical magnetic devices were obtained by annealing at 750°C. Furthermore, we attempted the preparation of well-crystallized NiZn ferrite thin films by adding hydrogen peroxide to the starting solutions.