Magnetic properties and nanostructure of FePt-TiN granular films deposited with N-2 gas addition for heat assisted magnetic recording media

Magnetic properties and nanostructure for FePt-30vol%TiN deposited while flowing N-2 gas are investigated. When N-2 gas addition of 3%-5% are introduced, compared with that of without N-2 gas, reduction in the lattice constant ratio and the unit cell volume, the increase in the degree of order of the granular film are observed. These indicate the segregation of Ti into grain boundaries as the result of the N-2 gas addition through nitridization of Ti dissolved in the FePt grains which lead to the enhancement of saturation magnetization, perpendicular magnetic anisotropy, and magnetic anisotropy field of the granular film. Therefore, magnetic decoupling in the FePt-TiN similar to the FePt-BN granular films is promoted by the segregation of nitrides formed by nitridization of metal element solidly soluble in FePt magnetic grains due to nitrogen deficiency.