TY - JOUR
T1 - Orthorhombic to trigonal phase transition of perovskite-type (Ndx,Sm1 - X)AlO3
AU - Yoshikawa, Akira
AU - Saitow, Akihiro
AU - Horiuchi, Hiroyuki
AU - Shishido, Toetsu
AU - Fukuda, Tsuguo
N1 - Funding Information:
This work was financially supported by Grant-in-Aid for General Scientific Research (B)-07459008(HH) and Scientific Research on Priority Area 09242208(HH) and 07230102(TS) of the Ministry of Education, Science and Culture of Japanese Government. This investigation was carried out under the Inter-University Cooperative Research Program of the Institute for Materials Research, Tohoku University, Japan.
PY - 1998/2/20
Y1 - 1998/2/20
N2 - 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+.
AB - 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+.
KW - Phase diagram of RAlO
KW - Phase transition
KW - Structure of (Nd,Sm)AlO
KW - X-ray diffraction
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U2 - 10.1016/S0925-8388(97)00449-0
DO - 10.1016/S0925-8388(97)00449-0
M3 - Article
AN - SCOPUS:0031997677
SN - 0925-8388
VL - 266
SP - 104
EP - 110
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1-2
ER -