Superparamagnetic, nanocrystalline cobalt nickel zinc ferrite thin films, deposited at sub-200°C for RF CMOS applications

Abstract

We demonstrate strongly oriented nanocrystalline, CMOS-compatible cobalt nickel zinc ferrite thin films, deposited at 190oC using a microwave-assisted synthesis technique. The crystallite size is optimized to be around 6 nm to yield a very high saturation magnetization (Ms=175 emu/cc at 300 K) and very low coercivity (32 Oe), suitable for GHz RF applications. Temperature-dependent magnetization measurements reveal that the films exhibit superparamagnetic behavior.