Fabrication of highly [001] oriented L10 FePt thin film using NiTa seed layer

A highly [001] oriented L1₀ FePt thin film has been successfully fabricated on glass disk substrates by using Ni-Ta alloy seed layer with O₂ exposure process. The [001] orientation of Fe-Pt was improved by exposing Ni-Ta surface to O₂ ambient in the deposition process of Ni-Ta/Cr/Pt/Fe-Pt film. An excess O₂ exposure degrades the coercivity because of the suppression of the ordering of FePt. Under the optimum O₂ exposure condition, perpendicular coercivity of as large as 6.9 kOe was achieved with good squareness and little remanence in the in-plane magnetization curve for the film stack of Ni-Ta (5 nm)/Cr (5 nm)/Pt (10 nm)/Fe-Pt (10 nm)/C (7 nm) structure. The total thickness of the underlayers is as thin as 20 nm.