CoPrCr-SiO2 Longitudinal Media for the Next Generation Magnetic Tapes

To improve recording density of magnetic tape systems, CoPtCr based sputtered media have been investigated, which achieved coercivity of 2600 Oe higher than conventional Co-CoO obliquely evaporated media. Recently, SiO₂ added CoPtCr granular media, which are largely researched for perpendicular recording media, have also showed beneficial effects on enhancing isolation and fine structure of magnetic particles for longitudinal recording magnetic tapes. Regarding with forming magnetic tape media on a flexible film by sputtering, one of the most difficult problems is film melting by heat during the deposition process. In addition, tape bend by internal stress of sputtered layer cause a disadvantage in reading and writing by magnetic heads in the magnetic tape system, therefore, the thickness of underlayer should be reduced to release the stress. With Ru/TiW underlayers, we found out the optimum deposition condition for each layer and magnetic layer composition to obtain the highest coercivity with an excellent longitudinal crystalline orientation. We report the results and its potentiality for magnetic tape system application.