Polarized Raman Spectra of Single Crystals of BaCeO3

Abstract

Crystals of BaCeO3 were obtained by the zone melting technique using an induction heating system. The crystals were studied by Raman spectroscopy at 10–983 K. They were found to be completely free from ceria, in contrast to the compounds obtained previously by the usual powder method. Single crystals (typically of 20 μm3) were identified and properly oriented under the microscope in order to give the largest Raman intensity contrasts when varying the polarization of the incident and scattered light. Five types of polarized spectra were obtained. The polarization data allowed the identification of 18 distinct bands among the 24 expected Raman-active modes of the low-temperature orthorhombic phase. These bands were tentatively assigned in terms of symmetry. A progressive gain of polarization of the bands was observed when a properly oriented crystal was submitted to thermal cycles between 25 and 600°C. © 1997 by John Wiley & Sons, Ltd.