Phase separation in Ca substituted YBCO

Palles, D; Lampakis, D; Bottger, G; Liarokapis, E; Kaldis, E

dc.contributor.author	Palles, D	en
dc.contributor.author	Lampakis, D	en
dc.contributor.author	Bottger, G	en
dc.contributor.author	Liarokapis, E	en
dc.contributor.author	Kaldis, E	en
dc.date.accessioned	2014-03-01T01:15:46Z
dc.date.available	2014-03-01T01:15:46Z
dc.date.issued	2000	en
dc.identifier.issn	0921-4534	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13735
dc.subject	Charge Distribution	en
dc.subject	Hydrostatic Pressure	en
dc.subject	Phase Separation	en
dc.subject	Room Temperature	en
dc.subject.classification	Physics, Applied	en
dc.title	Phase separation in Ca substituted YBCO	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0921-4534(00)01132-1	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0921-4534(00)01132-1	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	A room temperature micro-Raman spectroscopic study at hydrostatic pressures up to 4GPa has been carried out on Y1-xCaxBa2Cu3O7-delta polycrystalline superconducting compounds with x = 0.00-0.20 and delta = 0.045-0.005. Apart from the five strong Raman active phonons (4A(g) + 1B(1g)-like), additional structures have been observed in the y(cc)(y) over bar (402 cm(-1)) and the y(xx)(y) over bar (300 and 322 cm(-1)) scattering configurations with increasing intensities with the Ca content. The modes that appear in the out-of-phase B-1g phonon of O-pl are related to the disorder introduced by the Ca substitution for Y and to a local mode induced by the Ca atoms. The variation, with x, of the relative intensities of the constituent peaks of the O-pl in-phase phonon indicates that this phonon behavior depends on the amount of oxygen and not the concentration of the Ca substitution introduced carriers. There seem to exist two oxygen content differentiated phases which are present also in the pure oxygen overdoped YBCO. The insensitivity of the O-pl in-phase mode frequency combined with the behavior of the O-apex phonon, can be attributed to the excess charge distribution away from the CuO2 planes. A phase separation seems to be induced for hydrostatic pressures above 3GPa possibly related to the Ca atom cluster formation.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	PHYSICA C	en
dc.identifier.doi	10.1016/S0921-4534(00)01132-1	en
dc.identifier.isi	ISI:000165856000032	en
dc.identifier.volume	341	en
dc.identifier.spage	2149	en
dc.identifier.epage	2150	en