Ar+ ion milling-induced suppression of surface oxidation in Fe70Co30 thin films

•Depth-resolved XAS reveals that surface oxidation is suppressed by ion milling.•Selective oxidation and segregation of Fe proceed at the surface.•Milling-induced structural disorder results in suppression of Fe segregation.•Surface oxidation is suppressed because Co is robust against the oxidation.•Such information may give prospect for designing high-density storage devices.

We show from the depth-resolved X-ray absorption analysis that the degree of surface oxidation of Fe70Co30 thin films is reduced by Ar+ ion milling even if the film is exposed to air after ion milling. The milled film has thinner surface oxide layer and smaller ratio of Fe oxide component in the surface layer than those of the as-deposited film. It is also indicated that selective oxidation of Fe proceeds accompanied by the movement of Fe atoms toward the surface. The suppression of oxidation is explained by the obstruction of Fe movement toward the surface by the milling-induced disorder.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide