The magnetic properties and microstructure of strontium ferrite films with perpendicular and in-plane magnetic anisotropy

The texture and the easy axis of magnetization of strontium ferrite (SrFe/sub 12/O/sub 19/) thin films can be controlled by changing the power of the rf sputtering. In-plane magnetic anisotropy is developed at a sputtering power of 330 W (7.5 W/cm/sup 2/), whereas strong perpendicular magnetic anisotropy (Ku/spl sim/1/spl times/10/sup 6/ erg/cc) is induced at 60 W power (1.3 W/cm/sup 2/). Further control over coercivity and morphology can be achieved by changing the ratio R, between oxygen and argon in the sputtering gas. Coercivity decreases with R. Films deposited without oxygen exhibit higher coercivity and less intergranular interaction as compared to films sputtered with oxygen.