High-Temperature Phase Transition in Lanthanum Titanate Perovskites

Masatomo YASHIMA; Mizuki MORI; Roushown ALI; Takashi KAMIYAMA; Masahiko TANAKA; Koh SAITOH; Kenji TSUDA; Takeharu MORI; Ken-ichi OIKAWA; Akinori HOSHIKAWA; Shuki TORII

doi:10.14853/pcersj.2003F.0.1015.0

16th Fall Meeting of The Ceramic Society of Japan & The 5th International Meeting of Pacific Rim Ceramic Societies(PacRim5)

Session ID : 21-O-09

DOI https://doi.org/10.14853/pcersj.2003F.0.1015.0

Conference information

Host: The Ceramic Society of Japan

High-Temperature Phase Transition in Lanthanum Titanate Perovskites

*Masatomo YASHIMA, Mizuki MORI, Roushown ALI, Takashi KAMIYAMA, Masahiko TANAKA, Koh SAITOH, Kenji TSUDA, Takeharu MORI, Ken-ichi OIKAWA, Akinori HOSHIKAWA, Shuki TORII

Author information

*Masatomo YASHIMA
Department of Materials Science and Engineering, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, JAPAN
Mizuki MORI
Department of Materials Science and Engineering, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, JAPAN
Roushown ALI
Department of Materials Science and Engineering, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, JAPAN
Takashi KAMIYAMA
Neutron Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, JAPAN
Masahiko TANAKA
Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, JAPAN
Koh SAITOH
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, JAPAN
Kenji TSUDA
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, JAPAN
Takeharu MORI
Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, JAPAN
Ken-ichi OIKAWA
Neutron Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, JAPAN
Akinori HOSHIKAWA
Neutron Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, JAPAN
Shuki TORII
Satellite Venture Business Laboratory, Ibaraki University, JAPAN

CONFERENCE PROCEEDINGS FREE ACCESS

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Abstract

High-temperature phase transition of lanthanum niobium titanate La_0.64(Ti_0.92,Nb_0.08)O₃ has been studied using neutron powder diffraction and the Rietveld method (RIETAN-2001T). The material is orthorhombic (Cmmm) between 295 K and 534 K, while it is tetragonal (P4/mmm) at 637 K and 740 K. The tilt of the oxygen octahedron around Ti and Nb atoms was found to induce the tetragonal-to-orthorhombic phase transition. The angle of the tilt and the b/a ratio of cell parameters decrease with an increase of temperature and become 0 deg. and unity, respectively, at a transition temperature between 534 and 637 K.Both high- and low-temperature structures were in situ investigated by synchrotron radiation powder diffraction technique. Electron density distribution was obtained by the combination of the Rietveld refinement (RIETAN-2000) and maximum entropy method(Enigma and/or PRIMA).

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