Abstract
The rf magnetron-sputtered nickel ferrite thin films were prepared by using several kinds of target on glass, silicon, quartz, and alumina substrates. Single-phase nickel ferrite films were successfully deposited by using a nickel ferrite bulk target. The films deposited as a substrate temperature (Ts) of 250°C had a high coercivity of 2300 Oe. Investigation of the reasons for this high coercivity revealed that one of the causes was a very large expansion of the lattice of the spinel structure for the nickel ferrite film, which distorted the magnetic anisotropy. Another was the presence of Ni3+ ions, which have the same electron configuration as Co2+ ions, whose crystalline magnetic anisotropy is large.
