Nanogranular TiN-ZrO₂ intermediate layer induced improvement of isolation and grain size of FePt thin films

The effects of TiN-ZrO₂ intermediate layer on the microstructures and magnetic properties of FePt films were investigated. The TiN-ZrO2 intermediate layer was granular consisting of grains of solid solution of Ti(Zr)ON segregated by amorphous ZrO₂. By doping ZrO₂ into TiN intermediate layer, the FePt grains became better isolated from each other and the FePt grain size was reduced. For 20 vol. % ZrO₂ doping into TiN, the grain size decreased dramatically from 11. 2 nm to 6. 4 nm, and good perpendicular anisotropy was achieved simultaneously. For the FePt 4nm-SiO₂ 35 vol. % -C 20 vol. % films grown on top of the TiN-ZrO₂ 20 vol. % intermediate layer, well isolated FePt (001) granular films with coercivity higher than 18. 1 kOe and an average size as small as 6. 4 nm were achieved.