RF-bias effect on structural and magnetic properties in CoCrPt/Cr75Ti25/CoTi trilayer type longitudinal recording media

Abstract

The effects of an rf substrate bias on the structural and magnetic properties of the CoCrPt/Cr75Ti25/CoTi trilayer type longitudinal recording media deposited on glass substrate have been studied. It was found that the coercivity of 30 nm thick CoCrPt films deposited on Cr75Ti25/CoTi underlayer was 4000 Oe by a substrate bias of 100 W rf, which is 800 Oe increase than the non-biased case. X-ray diffraction indicated that the rf-bias to substrate improved the Co (<10(1)over bar0>) and (<11(2)over bar0>) plane textures of the CoCrPt magnetic layer. From RES analyses, Pt content of the CoCrPt magnetic layer increased with rf-bias power. In addition to the Pt increase, a better lattice matching between the CoCrPt magnetic layer and the Cr75Ti25/CoTi underlayer was obtained through the expansion of the lattice parameter, "a" and "c" of Co in the CoCrPt with the substrate bias. These two factors are thought to be the origin of the coercivity increase.