title: The checkerboard pattern of Bi(0.63)Sr(0.37)MnO(3) determined using resonant x-ray scattering at the Mn K edge.
abstract: A study using resonant x-ray scattering at the Mn K edge has been carried out on a Bi(0.63)Sr(0.37)MnO(3) single crystal. This compound undergoes a metal-insulator phase transition to the so-called charge ordered (CO) state at about 530 K. Strong resonance signals were observed at room temperature as the energy was tuned through the Mn K edge for several superstructures of the CO phase. The energy, polarization and azimuth angle dependences agree with a checkerboard ordering in the ab plane of manganese atoms of two types, in terms of their different local geometrical structures. One of the sites is anisotropic-a tetragonal distorted oxygen octahedron-and the other is isotropic-a nearly undistorted one, as observed for Bi(0.5)Sr(0.5)MnO(3) and other half-doped manganites. This result indicates that the checkerboard pattern is strongly stable and extends to doping concentrations x<0.5. No superstructures corresponding to the doubling of the c axis were detected. Intermediate valence states lower than 3.5, according to the fractional charge segregation, were deduced for the two non-equivalent Mn atoms, i.e. Mn(3.30+) and Mn(3.44+).
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009-Zaragoza, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Subías
authors.forename: M C
authors.initials: MC
authors.lastname: Sánchez
authors.forename: J
authors.initials: J
authors.lastname: García
authors.forename: J
authors.initials: J
authors.lastname: Blasco
authors.forename: J
authors.initials: J
authors.lastname: Herrero-Martín
authors.forename: C
authors.initials: C
authors.lastname: Mazzoli
authors.forename: P
authors.initials: P
authors.lastname: Beran
authors.forename: M
authors.initials: M
authors.lastname: Nevřiva
authors.forename: J L
authors.initials: JL
authors.lastname: García-Muñoz