Effects of argon pressure and substrate heating on the chromium underlayer used for high-density longitudinal CoNiCr media

Abstract

Sputtered CoNiCr on Cr is one of the preferred material systems for high-density longitudinal recording media. dc magnetron sputtered Cr films, on Al substrates, were investigated for the effects of argon pressure and substrate temperature on the microstructure. High-resolution scanning electron micrographs reveal that the films made at lower argon pressures have acicular-shaped grains changing to faceted grain structures at higher argon pressures. The effect of substrate heating prior to deposition was to change the structure from acicular shape to cubic shape. X-ray diffraction work reveals a bcc(110) orientation for films deposited at lower argon pressures changing to a mixed phase at higher argon pressures. Increased substrate temperature caused a mixture of (110) and (200) orientation.