RAMAN AND MOSSBAUER STUDY OF THE PSEUDO-ORTHORHOMBIC-TO-TETRAGONAL PHASE-TRANSITION IN YBA2(CU1-XFEX)3O7-DELTA (0.02-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.15)

ILIEV, M; ATANASSOVA, Y; BOZUKOV, L; TIHOV, J; HADJIEV, VG; LIAROKAPIS, E

dc.contributor.author	ILIEV, M	en
dc.contributor.author	ATANASSOVA, Y	en
dc.contributor.author	BOZUKOV, L	en
dc.contributor.author	TIHOV, J	en
dc.contributor.author	HADJIEV, VG	en
dc.contributor.author	LIAROKAPIS, E	en
dc.date.accessioned	2014-03-01T01:41:30Z
dc.date.available	2014-03-01T01:41:30Z
dc.date.issued	1992	en
dc.identifier.issn	0921-4534	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/23510
dc.subject.classification	Physics, Applied	en
dc.subject.other	UNTWINNED SINGLE-CRYSTALS	en
dc.subject.other	CHARGE REDISTRIBUTION	en
dc.subject.other	YBA2CU3O7-DELTA	en
dc.subject.other	SPECTRA	en
dc.subject.other	SCATTERING	en
dc.subject.other	SUBSTITUTION	en
dc.subject.other	SUPERCONDUCTORS	en
dc.subject.other	DIFFRACTION	en
dc.subject.other	NEUTRON	en
dc.subject.other	PHONONS	en
dc.title	RAMAN AND MOSSBAUER STUDY OF THE PSEUDO-ORTHORHOMBIC-TO-TETRAGONAL PHASE-TRANSITION IN YBA2(CU1-XFEX)3O7-DELTA (0.02-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.15)	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	1992	en
heal.abstract	The polarized Raman spectra from microcrystals of YBa2(Cu1-xFex)3O7-delta (0.02 less-than-or-equal-to x less-than-or-equal-to 0.15) were studied in various scattering configurations allowing one to follow the variations with x of both diagonal (A(g)) and non-diagonal (B2g and B3g) Raman modes. It was found that the splitting of the strongest in intensity B2g, B3g Raman pair at 210 and 300 cm-1 associated with O(4) vibrations along a and b, respectively, decreases slightly with x, thus indicating that in a microscopic scale the structure remains orthorhombic over the whole substitutional range. The Mossbauer spectra for x = 0.05, 0.10, and 0.15 showed a superlinear increase of the number of five-fold oxygen-coordinated Fe-atoms at the Cu(1)-sites. This is consistent with the assumption that Fe-clusters are formed along the <110> microtwin boundaries at higher x. In this sense YBa2(Cu1-xFe)3O7-delta could be considered as a two-phase system. The observed splitting of the A(g) Raman mode of Ba at x greater-than-or-equal-to 0.07 supports such an assumption. The Fe substitution increases the local disorder thus inducing additional Raman scattering of one-phonon density-of-states origin with a maximum at 580 cm-1.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	PHYSICA C	en
dc.identifier.isi	ISI:A1992HJ68800018	en
dc.identifier.volume	191	en
dc.identifier.issue	3-4	en
dc.identifier.spage	419	en
dc.identifier.epage	428	en