Raman study of the oxygen anharmonicity in YBa{sub 2}Cu{sub 3}O{sub {ital x}} (6.4{lt}{ital x}{lt}7.0) superconductors

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.54.6721· OSTI ID:392709

Palles, D; Poulakis, N; Liarokapis, E ^[1]; Conder, K; Kaldis, E ^[2]; Mueller, K A ^[3]

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1. Physics Department, National Technical University, Athens 157 80 (Greece)
2. Laboratorium fuer Festkoerperphysik, Edgenoessische Technische Hochschule Honggerberg, CH-8093 Zuerich (Switzerland)
3. IBM Zuerich Research Lab. Saumerstr. 4, CH-8803 Rueschlikon (Switzerland)

A systematic Raman study in the visible and the near IR has been carried out on YBa{sub 2}Cu{sub 3}O{sub {ital x}} samples, with isotopic substitution of {sup 18}O for {sup 16}O, and for oxygen concentrations in the range {ital x}=6.44{endash}6.98. A small but clear deviation from harmonic behavior has been detected for the frequency shift of the in-phase mode and, to a less extent, of the apex mode, relative to the out-of-phase phonon. The deviation increases towards low concentrations of oxygen. A disagreement of the present work for the apical mode, with a previous investigation using IR excitation, is attributed to the contribution of several phases to the apex mode in the underdoped region and the possible IR resonance of the {open_quote}{open_quote}ortho-II{close_quote}{close_quote} phase. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 392709
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 9 Vol. 54; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANHARMONIC CRYSTALS
BARIUM OXIDES
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
ISOTOPE EFFECTS
NEAR INFRARED RADIATION
PHASE STUDIES
RAMAN SPECTRA
TEMPERATURE RANGE 0065-0273 K
VISIBLE RADIATION
YTTRIUM OXIDES