Perpendicular magnetic anisotropy of FePt-Ag composite film onto amorphous substrate

A double-layered type film of glass/MgO 10 nm/Cr 70 nm/(Fe--Si 50 nm/Cr 10 nm)₅/Fe-Si 50 nm/MgO 5 nm/(FePt 2 nm/Ag 5 nm)₅ is synthesized on a glass substrate. The epitaxial growth in the film is preserved before and after annealing at 550°C for 1 h, resulting in L1₀ FePt with a [001] texture. The multilayer structure in the soft magnetic underlayer of (Fe--Si/Cr)₅ contributes to the good epitaxial growth. The film of (FePt/Ag)₅ shows FePt grains as small as 13 nm in size and a loop slope at coercivity α as small as 2 after anneal at 550°C for 1 h.