Pressure and temperature-dependent Raman study of YLiF4

Sarantopoulou, E; Raptis, YS; Zouboulis, E; Raptis, C

dc.contributor.author	Sarantopoulou, E	en
dc.contributor.author	Raptis, YS	en
dc.contributor.author	Zouboulis, E	en
dc.contributor.author	Raptis, C	en
dc.date.accessioned	2014-03-01T01:15:04Z
dc.date.available	2014-03-01T01:15:04Z
dc.date.issued	1999	en
dc.identifier.issn	0163-1829	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13326
dc.subject	Temperature Dependence	en
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	FLUORIDE SCHEELITES	en
dc.subject.other	LATTICE-VIBRATIONS	en
dc.subject.other	LIYF4	en
dc.subject.other	ND	en
dc.subject.other	SPECTROSCOPY	en
dc.subject.other	SCATTERING	en
dc.subject.other	ABSORPTION	en
dc.subject.other	CONSTANTS	en
dc.subject.other	DYNAMICS	en
dc.subject.other	YLF	en
dc.title	Pressure and temperature-dependent Raman study of YLiF4	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevB.59.4154	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevB.59.4154	en
heal.language	English	en
heal.publicationDate	1999	en
heal.abstract	Raman scattering spectra of single crystals of YLiF4 have been measured over wide ranges of hydrostatic pressures (0-20 GPa) and temperatures (30-1000 K). Unlike other members of the scheelite crystal class, the internal modes of YLiF4 due to vibrations within the LiF4-3 tetrahedra display large partial derivative omega/partial derivative P and partial derivative omega/partial derivative T slopes. In contrast, all four external modes corresponding to lattice translations show small partial derivative omega/partial derivative P slopes, with one of them (whose observation from the pressure cell is clear) also showing a small partial derivative omega/partial derivative P slope. These results suggest that temperature or pressure affect primarily the dynamics of the LiF4-3 group. This conclusion is further supported by an anharmonicity analysis in which the volume contribution to the total frequency shifts observed with temperature has been found very large for the internal modes. An abrupt change of slope in the frequency-versus-pressure diagrams of internal modes at 7 GPa is attributed to a stiffening of the LiF4-3 group. From the anharmonicity analysis, it is concluded that the internal binding in the LiF4-3 tetrahedra is essentially of ionic character. [S0163-1829(99)09805-7].	en
heal.publisher	AMERICAN PHYSICAL SOC	en
heal.journalName	Physical Review B - Condensed Matter and Materials Physics	en
dc.identifier.doi	10.1103/PhysRevB.59.4154	en
dc.identifier.isi	ISI:000078699400031	en
dc.identifier.volume	59	en
dc.identifier.issue	6	en
dc.identifier.spage	4154	en
dc.identifier.epage	4162	en