MAGNETIC AND RECORDING PROPERTIES OF SPUTTERED COCRTA/CR THIN-FILM MEDIA

Abstract

The magnetic and recording properties of CoCrTa/Cr, longitudinal, magnetic, recording media, with various Or contents, were investigated by changing the deposition temperature, the Or thickness and the CoCrTa thickness. The Cr content of the CoCrTa magnetic layer was varied from 10 to 14 at % Or and the firms were deposited on textured NiP/AIMg substrates by direct-current (d.c.) magnetron sputtering. Both the circumferential magnetic coercivity (H-c) and the coercivity orientation ratio (Or) of the media increased as the deposition temperature increased. The optimum Or thickness was 50 similar to 70 nm; below this optimum value both H-c and the Or were small, and above this value the Or decreased. As the CoCrTa thickness increased, the Or continuously decreased, while H-c had a maximum of about 1600 Oe near the 40 nm thickness. The signal-to-noise ratio of the CoCrTa/Cr films increased as the deposition temperature, the Or thickness and the CoCrTa thickness increased. However, the bit shift was lowest when the thicknesses of the CoCrTa and Or layers were 50 similar to 60 nm and 50 similar to 70 nm, respectively. The CoCrTa magnetic films with 40 at % Or had the highest signal to noise ratio of 33 dB and the lowest bit shift of 9 ns. Our results showed that the Or factor is an important parameter for high-performance recording characteristics as is a high H-c.