Interfacial Effects of MgO Buffer Layer on Perpendicular Anisotropy of FePt Films

MgO buffer layer in FePt perpendicular media blocked diffusion from the CrRu underlayer and promoted epitaxial growth of the FePt L1 ₀ film. The MgO layer deposited at 50degC appeared continuous and the interface roughness between MgO and FePt decreased with increasing thickness up to 4 nm. The predominant FePt (001) texture slightly improved with increasing MgO thickness. At 350degC, deposited MgO (2-nm thickness) was discontinuous and island-like. For 8-nm-thick MgO, the FePt (001) dominated and FePt (111) almost disappeared. Defects such as grain boundaries, twin boundaries, and interface roughness contributed to the high coercivity as a result of high deposition temperature or small MgO thickness