title: First single-crystal synthesis and low-temperature structural determination of the quasi-2D quantum spin compound (CuCl)LaNb2O7.
abstract: We provide a full description of the first single-crystal synthesis of the low-dimensional quantum spin compound (CuCl)LaNb(2)O(7) through the low-temperature topotactic ion exchange route. Very fast diffusion of ion-exchanged CuCl and Cs ions is observed. In addition, thorough structure determination at very low temperature is outlined following use of single-crystal X-ray diffraction and powder neutron diffraction, taking advantage of the better sensitivity of the latter method for describing O and Cl atoms. State-of-the-art calculations (Maximum Entropy Method) are used for visualising the fine structural features of this unusual pseudo-tetragonal superstructure. Our study unambiguously throws light on the long-standing controversy concerning the crystal structure of this compound, and allows for a relevant description of its magnetic properties. Incidentally, it is demonstrated that the low-temperature structural model tentatively proposed very recently by Tsirlin et al. (Phys. Rev. B, 2010, 82, 054107), according to powder synchrotron X-ray diffraction, is correct.
authors: University of Rennes 1, Sciences Chimiques de Rennes, UMR 6226 CNRS-University of Rennes 1, Bât. 10B, Campus de Beaulieu, F-35042, Rennes, France. olivier.hernandez@univ-rennes1.fr
authors: Olivier J
authors: OJ
authors: Hernandez
authors: Cédric
authors: C
authors: Tassel
authors: Kunihiro
authors: K
authors: Nakano
authors: Werner
authors: W
authors: Paulus
authors: Clemens
authors: C
authors: Ritter
authors: Eric
authors: E
authors: Collet
authors: Atsushi
authors: A
authors: Kitada
authors: Kazuyoshi
authors: K
authors: Yoshimura
authors: Hiroshi
authors: H
authors: Kageyama