Disorder in Gd2Ti2O7 was investigated by near-edge X-ray-absorption fine structure and X-ray photo-electron spectroscopy. The near-edge X-ray-absorption fine structure showed that Ti4+ ions occupied octahedral sites with a tetragonal distortion induced by vacant O sites. O 1s XPS spectra obtained with a charge neutralization system from Gd2Ti2O7 (100) and a Gd2Ti2O7 pyrochlore used previously. Both yielded a single peak, unlike the previous result on the latter that found 2 peaks. The current results gave no evidence for an anisotropic distribution of Ti and O. The extra features reported in a previous communication resulted from charging effects and incomplete surface cleansing. Thus, a result confirming the direct observation of simultaneous cation-anion antisite disordering and lending credence to the split vacancy model was clarified.

Probing Cation Antisite Disorder in Gd2Ti2O7 Pyrochlore by Site-Specific Near-Edge X-Ray Absorption Fine Structure and X-Ray Photo-Electron Spectroscopy. P.Nachimuthu, S.Thevuthasan, M.H.Engelhard, W.J.Weber, D.K.Shuh, N.M.Hamdan, B.S.Mun, E.M.Adams, D.E.McCready, V.Shutthanandan, D.W.Lindle, G.Balakrishnan, D.M.Paul, E.M.Gullikson, R.C.C.Perera, J.Lian, L.M.Wang, R.C.Ewing: Physical Review B, 2004, 70[10], 100101 (4pp)