Structural and magnetic properties of NiZn ferrite films with high saturation magnetization deposited by magnetron sputtering

NiZn ferrite films with well-defined spinel crystal structure were in situ fabricated by radio frequency magnetron sputtering at room temperature. The microstructures and static magnetic properties of the films' dependence on the partial pressure ratio of argon to oxygen gas were investigated. Scanning electron microscope images indicated that all the films consisted of particles nanocrystalline in nature and the sizes increase as the ratio increases in the range of 10-25 nm. A large saturation magnetization (237.2 emu/cm3) and a minimum of coercivity (68 Oe) were obtained when the ferrite film was deposited in the ratio of 4:1. The complex permeability values (μ = μ′−iμ″) of the film were measured at frequency up to 5 GHz. It was shown that the film exhibited a large real part of permeability μ′ of 18 and a very high resonance frequency fr of 1.2 GHz. The results suggested that the NiZn ferrite film as-deposited in the ratio of 4:1 may be promised as magnetic medium in the application of integrated circuits operating at microwave frequencies.