Assignment and temperature dependence of the Raman modes of LiTaO3 studied over the ferroelectric and paraelectric phases

Raptis, C

dc.contributor.author	Raptis, C	en
dc.date.accessioned	2014-03-01T01:07:05Z
dc.date.available	2014-03-01T01:07:05Z
dc.date.issued	1988	en
dc.identifier.issn	0163-1829	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/9783
dc.subject.classification	Physics, Condensed Matter	en
dc.title	Assignment and temperature dependence of the Raman modes of LiTaO3 studied over the ferroelectric and paraelectric phases	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevB.38.10007	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevB.38.10007	en
heal.language	English	en
heal.publicationDate	1988	en
heal.abstract	The Raman spectra of single crystals of LiTaO3 have been studied over two phases in the temperature range 2901200 K. Assignments of normal Raman modes in both the ferroelectric and paraelectric phases are given using data from several scattering configurations and taking into account the directional properties (in the ferroelectric phase) and temperature dependence of observed phonons. The number of normal Raman modes observed in each phase (13 optical branches in the ferroelectric phase and 5 in the paraelectric phase) indicates a transition from a C3v to a D3d symmetry, a result that is in agreement with diffraction data. Most modes in the ferroelectric phase soften with increasing temperature, the only exceptions being three E symmetry modes which are temperature independent. In the paraelectric phase three modes soften with increasing temperature, while the other two appear to be T independent. The manner in which the Raman spectra vary with temperature supports the theory of the order-disorder mechanism for the transition and also suggests that an intermediate phase exists (mixing of the C3v and D3d symmetries) within a temperature range of about 100 K below the critical point. © 1988 The American Physical Society.	en
heal.publisher	AMERICAN PHYSICAL SOC	en
heal.journalName	Physical Review B	en
dc.identifier.doi	10.1103/PhysRevB.38.10007	en
dc.identifier.isi	ISI:A1988Q924400080	en
dc.identifier.volume	38	en
dc.identifier.issue	14	en
dc.identifier.spage	10007	en
dc.identifier.epage	10019	en