Pressure-induced lattice instabilities and superconductivity in YBa 2 Cu4 O8 and optimally doped YBa2 Cu3 O7-δ

Calamiotou, M; Gantis, A; Siranidi, E; Lampakis, D; Karpinski, J; Liarokapis, E

dc.contributor.author	Calamiotou, M	en
dc.contributor.author	Gantis, A	en
dc.contributor.author	Siranidi, E	en
dc.contributor.author	Lampakis, D	en
dc.contributor.author	Karpinski, J	en
dc.contributor.author	Liarokapis, E	en
dc.date.accessioned	2014-03-01T01:31:42Z
dc.date.available	2014-03-01T01:31:42Z
dc.date.issued	2009	en
dc.identifier.issn	1098-0121	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19892
dc.subject	barium compounds	en
dc.subject	doping profiles	en
dc.subject	electrical conductivity	en
dc.subject	equations of state	en
dc.subject	high-pressure effects	en
dc.subject	high-temperature superconductors	en
dc.subject	lattice constants	en
dc.subject	phonons	en
dc.subject	praseodymium compounds	en
dc.subject	Raman spectra	en
dc.subject	superconducting transition temperature	en
dc.subject	yttrium compounds	en
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	PHASE-SEPARATION	en
dc.subject.other	DIFFRACTION	en
dc.subject.other	DEPENDENCE	en
dc.subject.other	GPA	en
dc.subject.other	TC	en
dc.title	Pressure-induced lattice instabilities and superconductivity in YBa 2 Cu4 O8 and optimally doped YBa2 Cu3 O7-δ	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevB.80.214517	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevB.80.214517	en
heal.identifier.secondary	214517	en
heal.language	English	en
heal.publicationDate	2009	en
heal.abstract	Combined synchrotron angle-dispersive powder diffraction and micro-Raman spectroscopy are used to investigate pressure-induced lattice instabilities that are accompanied by superconducting Tc anomalies in YBa2 Cu 4 O8 and optimally doped YBa2 Cu3 O7-δ, in comparison with the nonsuperconducting PrBa2 Cu3 O6.92. In the first two superconducting systems there is a clear anomaly and hysteresis in the evolution of the lattice parameters and increasing lattice disorder with pressure, which starts at 3.7 GPa. On the contrary, in the Pr compound the lattice parameters follow very well the expected equation of state (EOS) up to 7 GPa. The micro-Raman data of the superconducting compounds show that the energy and width of the Ag phonons exhibit anomalies over the same pressure range where the lattice parameters deviate from the EOS and the average Cu2 -Opl bond length exhibits a strong contraction that correlates with the nonlinear pressure dependence of Tc. The anomalous Raman behavior is not observed for the nonsuperconducting Pr compound, clearly indicating a connection with the charge carriers. It appears that the cuprates close to optimal doping are at the edge of lattice instability. © 2009 The American Physical Society.	en
heal.publisher	AMER PHYSICAL SOC	en
heal.journalName	Physical Review B - Condensed Matter and Materials Physics	en
dc.identifier.doi	10.1103/PhysRevB.80.214517	en
dc.identifier.isi	ISI:000273228200092	en
dc.identifier.volume	80	en
dc.identifier.issue	21	en