MAGNETIC RECORDING MEDIUM AND ITS PRODUCTION

摘要

PURPOSE: To produce a magnetic recording medium with an underlayer of a Cr alloy and a magnetic layer of a CoPt alloy having high coercive force and high squareness ratio and ensuring low medium noise. CONSTITUTION: This magnetic recording medium has a nonmagnetic underlayer 2 and a CoPt magnetic layer 3. The nonmagnetic underlayer 2 is one or more layers and the difference [d(002) -d(110) ] between the crystal lattice interplanar spacing of the hcp (002) faces of the magnetic layer and that of the bcc (110) faces of the nonmagnetic underlayer contg. Cr and Mo as principal components and kept in contact with the magnetic layer is 0.002-0.032Å. This magnetic recording medium may have one or more nonmangnetic underlayers between the nonmagnetic underlayer contg. Cr and Mo as principal components and the substrate, and the nonmagnetic underlayer kept in contact with the nonmagnetic underlayer contg. Cr and Mo as principal components has a body- centered close-packed crystal structure. This magnetic recording medium is produced by forming the nonmagnetic underlayer contg. Cr and Mo as principal components and the CoPt magnetic layer by sputtering at 250-425 deg.C heating temp. of the substrate under 0.5-10mTorr pressure of gaseous Ar.