ISSN:
1600-5767
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
Structural change caused by substitution of Nd for Sm in perovskite (Nd, Sm)AlO3 was analysed by application of high-resolution powder X-ray diffraction using synchrotron radiation. The parallel, well monochromated and bright incident X-rays improved the full width at half-maximum (FWHM) to 0.027° in a wide 2θ range for the standard Si powder. Applying this high-resolution optical system, the lattice parameters of the solid solution (Ndx, Sm_{1-x})AlO3 were precisely analysed for the phases from x = 0.0 to 1.0 with an interval of 0.2. The lattice parameters of a series of RAlO3 vary systematically with the average ionic radii of R^{3+}, accompanying a structural change from orthorhombic to a trigonal system at around R^{3+}=1.11 Å corresponding to average ionic radii of 0.7{\rm Nd}^{3+}+0.3{\rm Sm}^{3+}. In orthorhombic phases, deformation of the crystal lattice from its ideal cubic lattice is minimized at around x = 0.0–0.2 in (Ndx, Sm_{1-x})AlO3 and increased with increasing average ionic radii of Nd^{3+} and Sm^{3+}. The structure changes from orthorhombic to trigonal at around x = 0.7.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0021889898001629
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