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 500degreesC in air by a spray pyrolysis deposition method (SPD), where the film thickness was held at about 1 mum and the deposition rate was varied between 100 and 200 nm/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 600degreesC. Magnetic properties comparable with those of bulk NiZn ferrite and applicable to practical magnetic devices were obtained by annealing at 750degreesC. Furthermore, we attempted the preparation of well-crystallized NiZn ferrite thin films by adding hydrogen peroxide to the starting solutions.