2024-03-28T09:49:25Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/59402022-11-17T02:08:08Zhdl_2115_20045hdl_2115_139Oxide ion conduction mechanism in RE9.33(SiO4)6O2 and Sr2RE8(SiO4)6O2 (RE = La, Nd) from neutron powder diffractionMasubuchi, YujiHiguchi, MikioTakeda, TakashiKikkawa, ShinichiOxide ion conductorapatite-type structureconduction mechanismneutron diffractionmaximum entropy method428.4Oxide ion conduction mechanism was clarified by Rietveld and MEM analysis for both RE9.33(SiO4)6O2 and Sr2RE8(SiO4)6O2 (RE = La and Nd) in high purity using neutron powder diffraction data collected at room temperature. All compounds had an apatite type structure in space group P63/m. There was neither site splitting nor interstitial site of oxide ion. RE9.33(SiO4)6O2 had cation vacancies only at 4f site. In Sr2RE8(SiO4)6O2, the 4f sites were fully occupied by strontium and rare earth with a molar ratio of 1:1. Oxide ion at hexagonal channel site had large displacement along c-axis in RE9.33(SiO4)6O2. The large displacement is induced by cooperative rotation of SiO4 tetrahedra around rare earth in 4f site through oxide ion polyhedra around another rare earth in 6h site. The displacement, enhanced by a vacancy in the 4f site, is directly related to the oxide ion conduction in RE9.33(SiO4)6O2.Elsevier B.V.Journal Articleapplication/pdfhttp://hdl.handle.net/2115/5940https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/5940/1/SSI117-3-4.pdf0167-2738Solid State Ionics1773-42632682006-01enginfo:doi/10.1016/j.ssi.2005.09.015author