Orthorhombic to trigonal phase transition of perovskite-type (Ndx,Sm1 - X)AlO3

Akira Yoshikawa, Akihiro Saitow, Hiroyuki Horiuchi, Toetsu Shishido, Tsuguo Fukuda

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26 Citations (Scopus)


Phase transition of solid solution phases of (Ndx,Sm1 - x)AlO3 was investigated by powder X-ray diffraction technique. The transition temperature Tc from orthorhombic to trigonal structure is linearly related to x in (Ndx,Sm1 - x)AlO3 with the relation of Tc(°C) = -1043.4x+785.8 as an approximation at ambient pressure. This transition is reversible against the change of temperature. At room temperature, the structural change from orthorhombic to trigonal system takes place at around x=0.73 when x varies from 0.0 to 1.0 in (Ndx,Sm1 - x)AlO3. Thus, the average ionic radius of R3+ plays an important role to decide the structure of RAlO3, and an appropriate selection of ionic radius rR for R will function so as to control temperature and/or pressure for the structural change. As a result, structural diagram of RAlO3 given by temperature condition and atomic number of R, which implies a phase diagram under pressure and temperature conditions, was proposed. Change of molar volume of a series of RAlO3 was also discussed based on both effects of temperature and ionic radius R3+.

Original languageEnglish
Pages (from-to)104-110
Number of pages7
JournalJournal of Alloys and Compounds
Issue number1-2
Publication statusPublished - 1998 Feb 20


  • Phase diagram of RAlO
  • Phase transition
  • Structure of (Nd,Sm)AlO
  • X-ray diffraction

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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