Spray pyrolysis deposition of NiZn ferrite thin films

We have investigated for the preparation of NiZn ferrite thin films from Ni, Zn and Fe nitrates mixed aqueous solutions at a substrate temperature between 350 and 500 °C by a spray pyrolysis deposition (SPD). The crystallinity of the prepared NiZn ferrite films with the thickness of about 1 μm became higher with increasing substrate temperature during a film deposition, but these as-prepared films could not show sufficient magnetic properties for practical use. Post-preparation annealing above 600 °C was necessary to get enough magnetic properties. The NiZn ferrite film having the saturation magnetization of 0.37 T was obtained after annealing at 750 °C for 2 h in air and the value was very close to that of the bulk ferrite. Also, it is noted that the film exhibited very high magnetic resonance frequency exceeding the value from Snoekʹs limit for a bulk specimen.