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キーワード:
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要旨:
Single-phase mixed aluminates-titanates Pr1-xSrxAl1-xTixO3 (x = 0.1, 0.2, 0.3, 0.5, 0.7) with rhombohedral perovskite structure were prepared by solid-state reaction technique at 1823-1873 K. Morphotropic rhombohedral-to-cubic phase transition in Pr(1-x)Sr(x)Al(1-x)TixO(3) series is predicted to occur at x = 0.88. The temperature-induced structural phase transition R (3) over bar c - Pm (3) over barm in Pr0.5Sr0.5Al0.5Ti0.5O3, detected at 930 K by in situ high-temperature X-ray synchrotron powder diffraction, occurs at considerably lower temperature as the corresponding transformation in the parent compound PrAlO3 (1770 K). Such remarkable drop of the transition temperature is explained by gradual decrease of the perovskite structure deformation in the Pr1-xSrxAl1-xTixO3 series with increasing Sr and Ti contents as a consequence of the increasing Goldschmidt tolerance factor. For Pr0.3Sr0.7Al0.3Ti0.7O3 phase, a sequence of the low-temperature phase transformation R (3) over bar c - Immb(C2/m) - I4/mcm was detected.
