Raman and x-ray study of perovskite solid solutions
- 21 December 1998
- journal article
- Published by IOP Publishing in Journal of Physics: Condensed Matter
- Vol. 10 (50) , 11687-11702
- https://doi.org/10.1088/0953-8984/10/50/008
Abstract
La and Nd gallates are currently being used as substrate materials for high temperature superconductor thin film deposition. In this work we have synthesized and characterized by means of XRD and Raman spectroscopy solid solutions of the type . Polarized Raman study of and single crystals is also performed. Our results confirm the Pbnm space group for both La and Nd perovskites at room temperature and the centrosymmetric for in the high temperature phase. The orthorhombic to rhombohedral first order phase transition ( in ) is studied as a function of Nd substitution. increases quadratically with x for . Beyond x = 0.17 the phase transition, if present, is above the limit of our experimental setup (870 K). The detection of a soft mode in the rhombohedral phase is interpreted as due to the existence of a virtual second order transition to cubic symmetry at high temperature, analogous to that observed in rare earth aluminates.Keywords
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