HIGH RECORDING PERFORMANCE OF CO-CR MEDIUM SPUTTER-DEPOSITED AT HIGH AR PRESSURE AND HIGH SUBSTRATE-TEMPERATURE

Co-Cr films were prepared by sputter deposition at a high Ar pressure of 70 Pa with elevated substrate temperatures up to 400 degrees C. Fil ms of 100 nm thickness were deposited using a 19 at.% Cr-Co target ont o a well c-axis oriented Ti underlayer prepared on glass disk substrat es, The perpendicular coercivity, H-c perpendicular to, of the films i ncreased from 660 to 1940 Oe with increasing temperature. The films wi th high H-c perpendicular to exhibited a dense fine microstructure wit h distinct grain boundaries. The recording performance of the disk sam ples were measured by using a metal in gap type ring head, comparing w ith that of conventional Co-Cr films deposited at a low Ar pressure of 0.2 Pa. It was found that the high pressure deposited Co-Cr film exhi bited higher output by more than 2 dB at the densities below 320 kFRPI (flux reversals per inch) compared with the conventional film with th e same high coercivity. The D-50 of as high as 250 kFRPI and the high est recordable density of over 600 kFRPI were confirmed for the new ty pe of Co-Cr film deposited at 70 Pa and at 400 degrees C. The noise le vel of the film, however, was slightly higher than that of conventiona l method films, disagreeing with the suggestion of the microstructure. (C) 1996 American Institute of Physics.