Mn-Zn spinel ferrite thin films prepared by high rate reactive facing targets sputtering

Mn-Zn ferrite thin films were deposited by sputtering a Mn0.6Zn0.4Fe2 alloy target, which was fabricated by powder metallurgy, in a mixture gas of Ar and O2. A 12 nm thick Pt underlayer was deposited at a substrate temperature of 300 deg. C. All specimen films were prepared in a reactive facing targets sputtering system. The degree of oxidization of the film is strongly related to the oxidation condition at the surface of the target. The surface condition of the target can be estimated by monitoring the discharge voltage. The discharge current-voltage characteristics clarify that there are three regions for the surface condition of the target, i.e. ''oxidized,'' ''metallic,'' and ''transition.'' Mn-Zn ferrite films with (111) crystallite orientation were deposited on Pt(111) underlayer under the transition region condition. The film prepared at O2 partial pressure ratio of 25% revealed 4.8 kG of saturation magnetization 4πMs. The deposition rate of the reactive sputtering method is 16 times as high as that of the conventional method