Local Structure of Amorphous EuO-TiO^sub 2^ Thin Films Probed by X-Ray Absorption Fine Structure

We have investigated the local structure of amorphous oxides in EuO-TiO... system to understand the mechanism that gives rise to curious ferromagnetic properties recently observed in the system. X-ray absorption spectroscopy has been performed on amorphous EuTiO... and Eu...TiO... thin films prepared by the pulsed-laser-deposition method. The TiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data analyses reveal that the coordination number of Ti... in the amorphous thin films is around 4, which is in sharp contrast to their crystalline counterparts, where Ti... ions are octahedrally coordinated by oxide ions. It is therefore inferred that Ti... acts as a network-forming cation in the random network structure of the amorphous oxides. From the EuL...-edge EXAFS data analyses, it is found that the coordination number of Eu... is much lower and the nearest Eu-O bond length is shorter in the amorphous thin films than in the crystalline counterparts. The amorphization-induced enhancement of ferromagnetic interactions observed in the EuO-TiO... system is discussed in terms of the local environment around Eu... ions. (ProQuest: ... denotes formulae/symbols omitted.)