Fabrication of highly (001) oriented L10 FePt thin film using NiTa seed layer

A highly (001) oriented L1(0) FePt thin film has been successfully fabricated on glass disk substrates by using Ni-Ta alloy seed layer with O-2 exposure process. The (001) orientation of Fe-Pt was improved by exposing Ni-Ta surface to O-2 ambient in the deposition process of Ni-Ta/Cr/Pt/Fe-Pt film. An excess O-2 exposure degrades the coercivity because of the suppression of the ordering of FePt. Under the Optimum O-2 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.