Microstructure and magnetic properties of granular CoPtCr-SiO2 films on Ru seed layer

Granular-type [(Co-90 Cr-10) (85) Pt-15](89.8-) [SiO2](10.2) films were prepared by using cosputtering methods, with Ru as a seed layer. Influences of Ru thickness on the microstructure and magnetic properties of the CoPtCr-SiO2 magnetic layer were investigated. It was found that the seed layer obviously effected the grain isolation, c-axis distribution and magnetic parameters. The Ru seed layer with a suitable thickness is very helpful for achievement of high anisotropy, proper coercivity and high squareness. The anisotropy energy of the magnetic layer can be as high as 5 x 10(6) erg/cm(3) or more, even with a thin Ru layer, promising good thermal stability. It was noted that the Ru layer markedly enhanced the isolation of CoPtCr grains, corresponding to the increase of coercivity and the decrease of loop slope. Moreover, it was also revealed that the addition of SiO2 to CoPtCr effectively isolated the CoPtCr grains without disturbing the expitaxial growth of CoPtCr grains on the Ru seed layer.