Composition and Deposition Temperature Dependence of the Structure of Oxidized Thin Film Amorphous Tb-Fe.

Amorphous rare-earth transition-metal (alpha-RE-TM) alloys such as Tb-Fe (alpha-Tb-Fe) are the leading candidates for use in magnet-optic recording, a high bit-density read/write storage technology. A significant difficulty, however, lies in the stability of these materials with respect to oxidation. The present study is part of an ongoing investigation into the mechanism of oxidation of these alloys, the effect of oxidation on their magnetic properties, and means for stabilizing the alloys against oxidation or protecting them against oxidation by a coating. The microstructure of amorphous Tb-Fe alloy thin films prepared by magnetron co-sputtering and oxidized in air at 200C has been studied as a function of alloy composition and the substrate temperature at which the films were grown. Transmission electron microscopy and Auger electron spectroscopy with ion-sputter depth profiling were used to characterize the films. The composition of the alloy has no dramatic effect on the oxidation rate; it does, however, affect the microstructure of the alpha-Fe sub O sub 3 layer that forms on the alloy.