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Proceedings Paper

Superconducting La2CuO4+x prepared by oxygenation at high pressure: a Raman-scattering study
Author(s): Kevin F. McCarty; J. E. Schirber; S.-W. Cheong; Z. Fisk
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Paper Abstract

Superconducting crystals of La2CuO4+ prepared by high-pressure oxygenation have been analyzed by Ramán spectroscopy. A direct comparison of the role of excess oxygen was made by examining the same crystals with and without excess oxygen. La2CuO4+, like non-superconducting La2CuO4.O, is found to have a soft phonon that drives an orthorhombic to tetragonal phase transition. In both its tetragonal and orthorhombic forms, La2CuO4+ has a phonon peak at 630 cm1 that is absent in La2CuO4.O. The frequency of this peak is suggestive of a peroxide-like species in La2CuO4+. Surprisingly, the Ag phonons of La2CuO4.O and La2CuO4+ occur at essentially the same frequency. While La2CuO4.O has a well-defined peak from double-magnon scattering, no welldefined double-magnon scattering is observed in La2CuO4+, even in its phase-separated form.

Paper Details

Date Published: 1 November 1990
PDF: 9 pages
Proc. SPIE 1336, Raman and Luminescence Spectroscopies in Technology II, (1 November 1990);
Show Author Affiliations
Kevin F. McCarty, Sandia National Labs. (United States)
J. E. Schirber, Sandia National Labs. (United States)
S.-W. Cheong, Los Alamos National Lab. (United States)
Z. Fisk, Los Alamos National Lab. (United States)

Published in SPIE Proceedings Vol. 1336:
Raman and Luminescence Spectroscopies in Technology II
Fran Adar; James E. Griffiths, Editor(s)

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