Effect of Li2O Addition on the Preparation of (Y2‐yLiy)Ti2O7‐y |
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Authors: | Wen‐Ping Su Yu‐Hsuen Lee Ching‐Tien Hsieh Hwo‐Shuenn Sheu Jyh‐Fu Lee Yong‐Ping Chiang H.‐C. I. Kao |
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Affiliation: | 1. Department of Chemistry, Tamkang University, Tamsui 25137, Taiwan, R.O.C.;2. National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, R.O.C. |
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Abstract: | A new series of (Y2‐yLiy)Ti2O7‐y having an ordered pyrochlore phase was prepared by a solid state reaction method with a solid solution range of 0.05 ≥ y ≥ 0.10. Unit cell parameters obtained by the Rietveld refinement method shows that the a‐axis decreases linearly with increasing the amount of Li ion addition, indicating the successful incorporation of the Li ion into unit cell. The average x‐fractional coordinate of the O(1) site depends on the ionic radius ratio of r(A3+)/r(Ti4+) in the A2Ti2O7 with a pyrochlore phase. The Ti K‐edge XANES spectra of the (Y2‐yLiy)Ti2O7‐y show that the valence of the Ti ions is slightly less than 4 so that Ti is in the mixed valence state. Average particle size increases with increasing the amount of extra Li ion addition, which acts as a flux to lower the melting point of the materials. |
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Keywords: | (Y2‐yLiy)Ti2O7‐y Flux Pyrochlore SEM Ti K‐edge XANES |
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