title: Pressure-induced non-superconducting phase of β-Na0.33V2O5 and the mechanism of high-pressure phase transitions in β-Na0.33V2O5 and β-Li0.33V2O5 at room temperature.
abstract: The crystal structure of β-Na0.33V2O5 (C2/m, Z  =  6) has been studied on compression to 19 GPa at room temperature using synchrotron single-crystal diffraction in a diamond anvil cell. The vanadate bronze undergoes a phase transition to a non-superconducting phase at about 12 GPa due to changes of polyhedral connectivities in the vanadate framework and due to ordering of the Na(+) cations. This novel structure (Cm, Z  =  6) is interpreted as an intermediate stage in the sequence of pressure-induced transformations in the β-A0.33V2O5 bronzes (A: Li, Na) at room temperature. This study reveals the close relation between the loss of the two-leg ladder V-V system and non-superconducting state of the β-A0.33V2O5 materials.
authors.affiliation: Institute of Crystallography, RWTH Aachen University, 52060 Aachen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Grzechnik
authors.forename: Y
authors.initials: Y
authors.lastname: Ueda
authors.forename: T
authors.initials: T
authors.lastname: Yamauchi
authors.forename: M
authors.initials: M
authors.lastname: Hanfland
authors.forename: P
authors.initials: P
authors.lastname: Hering
authors.forename: V
authors.initials: V
authors.lastname: Potapkin
authors.forename: K
authors.initials: K
authors.lastname: Friese