Effect of FePt-C nucleation layer on magnetic properties and nanostructure for FePt-C / FePt-oxide stacked media

Abstract

Magnetic properties and nanostructure for FePt-30vol%C (2 nm) / FePt-30vol% GBM (0–8 nm) stacked media was investigated. Following effects of the employment of FePt-C nucleation layer (NL) were confirmed: 1) Msavevaries linearly against melting point (T m) with value (500–600 emu/cm3) smaller than that of media without NL (500–750 emu/cm3) due to volume average of Msave for FePt-C and FePt-GBM granular layer, 2) There is no strong correlation between grain diameter (GD) and degree of ordering (Sinfilm) of the stacked media with T m of the GBM, 3) Ku┴ film dependence on Sinfilm for media with NL shows similar behavior with that of without NL, 4) for media with the same total thickness, the smaller I110 inplane for media with NL than that of without NL reveals that disorder portion in the media with NL increases, 5) the improvement of linearity in I110 inplane for media with NL against total thickness suggests that the homogeneity of the media with is improved, 6) reduction of I100 linplane from XRD in-plane profile, reflected in ℓ4θsat from the torque curve which suggests the reduction of the ratio of FePt grains with their c-axes parallel to the film plane. Further effort would be required to completely exclude the in-plane component.