The anharmonic behavior of the oxygen modes in YBa2Cu3Ox compounds

Liarokapis, E; Palles, D; Conder, K; Kaldis, E

dc.contributor.author	Liarokapis, E	en
dc.contributor.author	Palles, D	en
dc.contributor.author	Conder, K	en
dc.contributor.author	Kaldis, E	en
dc.date.accessioned	2014-03-01T01:17:13Z
dc.date.available	2014-03-01T01:17:13Z
dc.date.issued	2001	en
dc.identifier.issn	0377-0486	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14399
dc.subject.classification	Spectroscopy	en
dc.subject.other	barium	en
dc.subject.other	copper	en
dc.subject.other	oxygen	en
dc.subject.other	oxygen 18	en
dc.subject.other	yttrium	en
dc.subject.other	article	en
dc.subject.other	conductor	en
dc.subject.other	energy	en
dc.subject.other	Raman spectrometry	en
dc.subject.other	structure analysis	en
dc.subject.other	superconductor	en
dc.title	The anharmonic behavior of the oxygen modes in YBa2Cu3Ox compounds	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/jrs.771	en
heal.identifier.secondary	http://dx.doi.org/10.1002/jrs.771	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	The anharmonic behavior of the Raman-active oxygen modes was examined in YBa2Cu316,18 O-x compounds over the whole range of oxygen doping (6 < x < 7). The apex phonon of A(g) symmetry shows a small. anharmonicity in the range of 6.4 < x < 6.9, which can be attributed to the anharmonic behavior of this mode in one of the constituent phases (ortho-II, ortho-III, etc.), but not in the ortho-I phase. The B-1g mode does not show any anharmonicity over the whole range of oxygen doping, but characteristic spectral changes appear for x approximate to 6.3 and 6.7. At the lowest oxygen content studied (x = 6.03), there is a considerable amount of anharmonicity for the in-phase phonon of the plane oxygen atoms, which remains large until x approximate to 6.3, at the phase transition to the tetragonal phase, where it drops to zero. It increases again for x approximate to 6.4 and then gradually decreases with doping to disappear at the optimal doping. If these changes are combined with the spectral modifications of the B-1g and in-phase modes, they indicate that local structural changes are induced by the transfer of carriers to the CuO2 planes at x approximate to 6.3, which are related to the reduction in anharmonicity, the pinning of the carriers and superconductivity. Copyright (C) 2001 John Wiley & Sons, Ltd.	en
heal.publisher	JOHN WILEY & SONS LTD	en
heal.journalName	Journal of Raman Spectroscopy	en
dc.identifier.doi	10.1002/jrs.771	en
dc.identifier.isi	ISI:000171615300006	en
dc.identifier.volume	32	en
dc.identifier.issue	10	en
dc.identifier.spage	821	en
dc.identifier.epage	826	en