The effect of Ca substitution on the structure and the Raman active phonons in Y1-xCaxBa2Cu3O7-δ

Palles, D; Liarokapis, E; Leventouri, Th; Chakoumakos, BC

dc.contributor.author	Palles, D	en
dc.contributor.author	Liarokapis, E	en
dc.contributor.author	Leventouri, Th	en
dc.contributor.author	Chakoumakos, BC	en
dc.date.accessioned	2014-03-01T01:14:13Z
dc.date.available	2014-03-01T01:14:13Z
dc.date.issued	1998	en
dc.identifier.issn	0953-8984	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12937
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	RARE-EARTH	en
dc.subject.other	SUPERCONDUCTIVITY	en
dc.subject.other	MODES	en
dc.title	The effect of Ca substitution on the structure and the Raman active phonons in Y1-xCaxBa2Cu3O7-δ	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0953-8984/10/11/015	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0953-8984/10/11/015	en
heal.language	English	en
heal.publicationDate	1998	en
heal.abstract	Micro-Raman measurements and Rietveld refinements of x-ray data have been carried out in the superconducting system Y1-xCaxBa2Cu3O7-delta with 0 less than or equal to x less than or equal to 0.12, to delineate the effect of the excess doping on the Raman active phonons and especially on the characteristics of the plane oxygen modes. The increase of the Cu(2)-O(4) bond length with increasing Ca concentration induces a much smaller decrease in the frequency of the A(g) phonon of the apical 0(4) atom than the rare earth substitutions for Y. The frequency of the in-phase A(g) vibrations of the plane oxygens decreases slightly with increasing Ca content, but remains well above the lowest value that has been reported for the oxygen overdoped pure YBa2Cu3O7-delta compound, suggesting that the softening of this mode observed in those samples may not be attributed to the addition of carriers. The frequency of the out-of-phase B-1g-like vibrations of the plane oxygens is not affected by the substitution, but the width of the corresponding phonon increases considerably. This increase is due to the appearance of another mode of B-1g symmetry that could correspond to a hypothetical CaBa2Cu3O7-delta phase separated from the pure YBCO phase.	en
heal.publisher	IOP PUBLISHING LTD	en
heal.journalName	Journal of Physics Condensed Matter	en
dc.identifier.doi	10.1088/0953-8984/10/11/015	en
dc.identifier.isi	ISI:000072951000015	en
dc.identifier.volume	10	en
dc.identifier.issue	11	en
dc.identifier.spage	2515	en
dc.identifier.epage	2524	en