X-ray study of modulated structures of beta-Cu_xV₂O₅

High resolution X-ray study reveals the wave vector change in the modulated structure of the quasi-one dimensional compound beta'-Cu vanadium bronze. Structural modulation of the reduced wave vector q₀ = (0, 0.305, 0) emerges below 220 K in beta'-Cu_0.29V₂O₅ . For beta'-Cu_0.39V₂O₅, not the single q modulation but two kinds of modulations were observed. A three-fold superlattice structure with q1 = (0, 0.333, 0) appears below 210 K. An incommensurate modulated structure with q2 = (0, 0.26 ? 0.29, 0) coexists below 175 K, whose satellite intensity and b* component Qb have temperature and passing-time dependencies between 140 K and 175 K. The competition between q₁ and q₂ modulations was also observed. It seems that the q₂ is deeply related to the physical property change between 140 K and 180 K confirmed by the decrease in the magnetic susceptibility and the increase in the resistivity.

Published with permission from the copyright holder. This is the author's copy of the work, as published in Physica B, May 2003, Volume 329-333, Part 2 , Pages 713-714.
Publisher URL: http://dx.doi.org/10.1016/S0921-4526(02)02021-5
Copyright 2003 Elsevier B.V. All rights reserved.