title: "Devil's staircase"-type phase transition in NaV2O5 under high pressure.
abstract: The "devil's staircase"-type phase transition in the quarter-filled spin-ladder compound NaV2O5 has been discovered at low temperature and high pressure by synchrotron radiation x-ray diffraction. A large number of transitions are found to successively take place among higher-order commensurate phases with 2a x 2b x zc type superstructures. The observed temperature and pressure dependence of modulation wave number q(c), defined by 1/z, is well reproduced by the axial next nearest neighbor Ising model. The q(c) is suggested to reflect atomic displacements presumably coupled with charge ordering in this system.
authors.affiliation: Neutron Scattering Laboratory, Institute for Solid States Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohwada
authors.forename: Y
authors.initials: Y
authors.lastname: Fujii
authors.forename: N
authors.initials: N
authors.lastname: Takesue
authors.forename: M
authors.initials: M
authors.lastname: Isobe
authors.forename: Y
authors.initials: Y
authors.lastname: Ueda
authors.forename: H
authors.initials: H
authors.lastname: Nakao
authors.forename: Y
authors.initials: Y
authors.lastname: Wakabayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Murakami
authors.forename: K
authors.initials: K
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Amemiya
authors.forename: H
authors.initials: H
authors.lastname: Fujihisa
authors.forename: K
authors.initials: K
authors.lastname: Aoki
authors.forename: T
authors.initials: T
authors.lastname: Shobu
authors.forename: Y
authors.initials: Y
authors.lastname: Noda
authors.forename: N
authors.initials: N
authors.lastname: Ikeda