Effect of very thin Cr-underlayer on the magnetic and recording properties of CoCrTa thin-film media

A process has been developed which uses very thin Cr-underlayer for CoCrTa-media for high-density recording. The media sputtered using this technique revealed that by decreasing Cr-underlayer thickness from 2000 /spl Aring/ to 200 /spl Aring/, orientation-ratio increased from 1.27 to 1.6, squareness-ratio increased from 0.81 to 0.86, and Mrt increased from 3.25 to 3.97 memu/cm/sup 2/. The Mr value is increased because of the higher squareness. The higher Mr gives a higher Mrt product which produced higher signal output by about 10%. Also, the noise performance was comparable for the media with thin and thick Cr-underlayers. X-ray diffraction patterns showed strong in-plane preferred orientations, Cr(200) and Co(112~0) textures as a function of Cr-underlayer thickness.<
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