Suppression of in-plane (001) texture component in FePt-oxide granular films by adding a carbon buffer layer.

Investigation of magnetic properties and nanostructure of FePt-B₂O₃ granular film with carbon buffer layer (BL) of various thicknesses is reported. When the thickness of carbon BL is varied from 0 to 0.6 nm, saturation magnetization (M_s^film) is almost constant at around 750 emu/cm³ and perpendicular magnetic anisotropy (K_u⊥^film) changes from around 1.0×10⁷ to 2.0×10⁷ erg/cm³. For the granular film with the carbon BL thicker than 0.6 nm, both M_s^film and K_u⊥^film decrease. The reduction of M_s^film for the granular film by adding a carbon BL may be due to the alloying of carbon into the FePt magnetic grains. The enhancement of K_u⊥^film for the film with a 0.6 nm carbon BL is considered due to the reduction of the in-plane texture component which is supported by the in-plane XRD. The reduction of K_u⊥^film for the film with a carbon BL thicker than 0.6 nm is considered due to random growth of magnetic grains on a continuous carbon BL which is supported by the TEM cross-section images. According to these results, the employment of an un-continuous thin carbon BL is a promising method to enhance c-axis texture orientation of the FePt-oxide granular films. [ABSTRACT FROM AUTHOR]