Accessible Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag March 6, 2012

Reverse Monte Carlo study of Cu—O bond distortions in YBa2Cu3O6.9

Callum A. Young, Edward Dixon, Matthew G. Tucker, David A. Keen, Michael A. Hayward and Andrew L. Goodwin
From the journal

Abstract

A combination of neutron total scattering measäurement and reverse Monte Carlo (RMC) refinement is applied to the study of apical Cu—O bond distortions in the high-Tc superconductor YBa2Cu3O6.93. We show that the average structure is not consistent with a split-site model for the corresponding Cu and O positions, but that the local structure nevertheless reveals the existence of two separate apical Cu—O bond lengths. Using G(r) data obtained from a variety of Qmax values we show that this result is independent of the data treatment methodology. We also find that the resulting ‘short’ and ‘long’ Cu—O bond lengths agree well with the results of previous äEXAFS studies. The existence of bimodal apical Cu—O bond distributions in the context of a single-site average structure model is interpreted in terms of correlated displacements of the Cu and O atoms. We investigate the possibility of clustering of short apical Cu—O bonds within our RMC configurations.


* Correspondence address: University of Oxford, Department of Chemistry, South Parks Road, Inorganic Chemistry Laboratory, OX1 3QR Oxford, Großbritannien,

Published Online: 2012-03-06
Published in Print: 2012-05

© by Oldenbourg Wissenschaftsverlag, OX1 3QR Oxford, Germany