Deposition of Ba Ferrite Films for Perpendicular Magnetic Recording Media Using Mixed Sputtering Gas of Xe, Ar and O_2

摘要

Ba ferrite films were deposited epitaxially on ZnO underlayer from targets with composition of BaO-6.5Fe_2O_3 at substrate temperature of 600℃ using the facing targets sputtering apparatus. The gas mixture of Ar and Xe of 0.18 Pa and O_2 of 0.02 Pa was used as the sputtering gas and the dependences of crystallographic and magnetic characteristics on the partial Xe pressure P_(Xe) (0.0-0.18 Pa) were investigated. Films deposited at various P_(Xe) were composed of BaM ferrite and spinel crystallites, and the minimum centerline average roughness R_a of 8.3 nm was obtained at P_(Xe) of 0.10 Pa. Since saturation 4πM_s of 5.1 kG and perpendicular anisotropy constant K_(u1) of 4.23 x 10~5 J·m~(-3) were larger than those of bulk BaM ferrite of 4.8 kG and 3.30 x 10~5 J·m~(-3), respectively, these films appeared promising for use as perpendicular recording media.