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

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) M-s(ave) varies linearly against melting point (T-m) with value (500-600 emu/cm(3)) smaller than that of media without NL (500-750 emu/cm(3)) due to volume average of M-s(ave) for FePt-C and FePt-GBM granular layer, 2) There is no strong correlation between grain diameter (GD) and degree of ordering (S-in(film))of the stacked media with T-m of the GBM, 3) K-u perpendicular to(film) dependence on S-in(film) for media with NL shows similar behavior with that of without NL, 4) for media with the same total thickness, the smaller I-110(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 I-110(inplane) for media with NL against total thickness suggests that the homogeneity of the media with is improved, 6) reduction of I-001(inplane) from XRD in-plane profile, reflected in l(40)(sat) 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.