Perpendicular Co-Cr magnetic recording media prepared by sputtering using ECR microwave plasma

Perpendicular Co-Cr media were deposited on polyimide substrates by sputtering using an electron-cyclotron-resonance microwave plasma in an Ar sputtering gas pressure ranging from 3×10^-2 to 8×10^-2 Pa at a target to substrate distance from 170 to 230 mm. The accelerating voltage of the ions which bombard the media surface during deposition drastically affects the crystallographic and magnetic properties of Co-Cr films. Co-Cr media (50 nm in thickness) with good preferred crystal orientation (Δθ₅₀ less than 5 degrees), high perpendicular magnetic anisotropy (H_k higher than 4 kOe), high perpendicular coercivity (H_c⊥ over 1400 Oe) and no initial layer were successfully deposited when the ion accelerating voltage was reduced less than about 20 V