NiZn ferrite thin films prepared by Facing Target Sputtering

NiZn ferrite thin films with spinel structure have been deposited successfully on glass substrates at a relatively low temperature by means of the Facing Target Sputtering (FTS) technique. In addition to substrate temperature, PO₂/P (O₂ partial pressure over total sputtering pressure) ratio was found to be another major factor in controlling the in-plane coercivity H_c and saturation moment density M_s of NiZn ferrite thin films. The increase of M_s is attributed to the increase of the substrate temperature or the decrease of PO₂/P ratio; the decrease of H _c is associated with the increase of both substrate temperature and PO₂/P ratio. It is believed that the PO₂ /P ratio plays a critical role in the formation of NiZn ferrite film, which determines the magnetic properties of the film. With the increase of PO₂/P ratio, the NiZn thin film changes from a strong (111), (311) texture-dominated polycrystal structure to an amorphous structure and the grain size become smaller. In this study, sputtering conditions of NiZn ferrite films were optimized to achieve a low in-plane coercivity H_c and a relatively high saturation moment density M_s