Co-Cr Perpendicular Anisotropy Films Sputter-Deposited at Very High Ar Gas Pressures and Low Discharge Voltages

Co-Cr perpendicular magnetic films were sputter-deposited at extraordinarily high Ar gas pressures above 10 Pa at discharge voltages below 300 V. When films were deposited on glass substrates at Ar gas pressures above 10 Pa, they exhibited columnar structures with large grain sizes and poor crystal orientation, together with large squareness of the in-plane M-H loop. When Ti underlayers with a high perpendicular c-axis orientation (Δθ₅₀≈5°), were introduced, a high crystal orientation (Δθ₅₀<5°) and small squareness ratio (M_r///M_s≈0.2) were obtained for Co-Cr films deposited at 50 Pa. Films 200 nm in thickness showed fine columnar structures with distinct grains about 50 nm in diameter. This type of film is regarded as a possible candidate for high-density perpendicular recording media, achieved using a preparation method with improved discharge characteristics.