Platelet NaNbO3grown by single-step molten salt synthesis: Study on bismuth migration in topochemical conversion reaction

Takayuki Watanabe, Masatoshi Watanabe, Tatsuya Suzuki, Satoshi Yamabi, Hisato Yabuta, Kaoru Miura, Naoko Ito, Nobuhiro Kumada

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4 Citations (Scopus)


Platelet NaNbO3grains were grown at 1150-1225 °C by single-step molten salt synthesis. The structural and compositional transformation from the precursor Aurivillius phase to perovskite NaNbO3by the topochemical conversion reaction was studied. No compositional distribution was confirmed for the platelet grains grown at 1150 °C, whereas it was observed that the expulsion of bismuth and incorporation of sodium were simultaneously initiated in spots for the grains grown at 1170 °C. With increasing the growth temperature the topochemical conversion reaction was promoted, and single-phase NaNbO3 grains were eventually grown with heat treatment at 1225 °C for 6 h. In order to trace the structural transformation due to the topochemical conversion reaction, preconversion and postconversion platelet grains were chosen for characterizing the microstructure. It was found that the precursor Aurivillius phase is a mixed phase described as Bi2.5Nam-1.5NbmO3m+3(m = 5, 6, and 8). In the interior of the platelet grains, migration paths vertically elongated to the principal surface are created, and bismuth is expelled via the vertical path as well as the horizontal path along the (Bi2O2)2+layer. It was concluded that the distinctive migration network contributed to the structural transformation while maintaining the epitaxy

Original languageEnglish
Article number09PB08
JournalJapanese journal of applied physics
Issue number9
Publication statusPublished - Oct 1 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)


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