title: Structure refinements of Na0.8Ti1.2Ga4.8O10: X-ray diffraction analysis for the sodium ion distribution in a one-dimensional tunnel-like space.
abstract: The structure of Na0.8Ti1.2Ga4.8O10 was determined by means of single-crystal X-ray diffraction at 173 and 123 K and reinvestigated at 299 K. The host structure containing one-dimensional tunnels was retained over the temperatures examined, while significant changes were observed in the probability density distribution of Na+ ions in the tunnel. The refinement based on the local structure model with the deviated Na+ ion neighboring the vacancy gave a similar result to that from the conventional model, but with reduced standard uncertainties of the structural parameters for the Na+ ions. The potential barrier for the Na+ ion hopping between adjacent cavities was estimated to be ca 30-40 meV from the joint probability density function of deviated Na+ ions.
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. michiue.yuichi@nims.go.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Michiue
authors.forename: Akira
authors.initials: A
authors.lastname: Sato