FePt small-grain film with Au doping for high density perpendicular magnetic recording media

In this study, we focused on a FePtAu-C small-grain film specifically designed for very-high density perpendicular magnetic recording media, surpassing 1 Tbits/in2 density. The film layer had a composition of Fe47Pt43Au10-C40% with 7.2 nm thickness. It was deposited onto a silicon substrate with one 12 nm thick magnesium oxide sandwich-layer at 560 degrees C temperature. Notably, the film exhibited a perpendicular coercivity of 39 kOe. Based on transmission electron microscopy (TEM) analysis, the film small-grain size was determined to be approximately 8.2 +/- 1.6 nm. Furthermore, our investigation revealed that the grain size of magnesium oxide sandwich-layer was about 12 nm, which was larger than that of FePt. As a consequence, the FePt small-grains were not directly influenced by magnesium oxide small-grains beneath them. Moreover, a more in-depth examination using high-resolution TEM imaging demonstrated outstanding L10 ordering within the thin-film, corroborated by texture examination conducted via x-ray diffraction (XRD). It is noteworthy that magnesium oxide sandwich-layer exhibited a polycrystalline structure, while the FePt growing on top of magnesium oxide occurred in an epitaxial manner.