Effect of Na content and hydration on the excitation spectrum of the cobaltite NaxCoO2·yH2O
Journal
Journal of Physics Condensed Matter
Journal Volume
16
Journal Issue
11 SPEC. ISS.
Pages
S857-S865
Date Issued
2004
Author(s)
Lemmens, P.
Gnezdilov, V.
Kovaleva, N. N.
Choi, K. Y.
Sakurai, H.
Takayama-Muromachi, E.
Takada, K.
Sasaki, T.
Chen, D. P.
Lin, C. T.
Keimer, B.
Abstract
We report on a Raman scattering study of the superconducting cobaltite NaxCoO2·yH2O as function of Na content and hydration (x ≈ 1/3, 3/4 and y ≈ 0, 2/3, 4/3). The observed scattering intensity is analysed in terms of lattice strain, structural misfit and disorder. Hydration, due to the intercalation of one or two H2O layers, releases a part of this strain. Our Raman data suggest a connection between disorder on the partly occupied Na sites and the narrow phase space of superconductivity.
Type
journal article