Noriyasu Echigo

Effects of Incident Angle on Recording Properties of Vacuum Deposited Co-Cr Films

The recording characteristics of Co-Cr films were investigated with respect to the angle at which evaporated atoms are incident on the substrate during film deposition. The recording characteristics of Co-Cr films deposited at angles of incidence of 55° to 20° depend on the head scan direction. In the normal direction, the magnetization in the film is recorded mainly by the magnetic field near the leading edge of the head, while in the reverse direction it is written mainly by the field near the trailing edge. The single-peak-like isolated waveform in the normal head scanning direction is explained as the super-positioning of the waveform reproduced from the magnetization recorded by the head field near the leading edge, and the waveform from magnetization reversals at the film surface which are written by the field near the trailing edge. The reproduced voltage from the film medium decreases with increasing azimuth angle, owing to the magnetic anisotropy existing in the film plane, while Co-Cr films deposited at incident angles of 20° to ¿20° have almost the same density response at different azimuth angles.

Improvement of Performance in Continuously Vacuum Deposited Co-Cr Film by Substrate Treatment

Dependence of the perpendicular anisotropy of continuously vacuum deposited Co-Cr films on glow discharge treatment of the polymer base film surface, and on the thickness of a Ti underlayer, was investigated. The relation between the film microstructure and the recording characteristics of the Co-Cr film media was also studied. When the polymer film surface was pretreated by glow discharge with Ar gas, the Hkeff of the Co-Cr films decreased, but when H2 gas was used instead of argon, the deterioration of the Hkeff was negligible. Co-Cr films deposited on a Ti underlayer had a high Hkeff regardless of the glow discharge treatment conditions. The Ti underlayers had to be more than 40 Å thick in order for the Co-Cr films to have a small ¿¿50, around 5 or 6°. The Co-Cr films showed a columnar structure when the Ti underlayer thickness was in the range from 100 to 2000 Å Co-Cr films with a columnar structure yielded a high reproduced voltage.