Electron Diffraction Study of an Inorganic Spin-Peierls System CuGeO₃

Structural analysis ofCuGeO3: Relation between nuclear structure and magnetic interaction

“…There is a rather small shift of the Ge site, and O͑2a͒ and O͑2b͒ can be refined without any restriction. The other space group proposed by Kamimura et al, 10 Bbmm was also tested. Whereas a similar description of the fundamental reflections can be achieved in Bbmm, the entire set including the superstructure reflections yields the much larger agreement factor, R w (F 2 )ϭ9.8%; the Bbmm space group can be definitely excluded.…”

“…The same type of superstructure reflection was also seen in electron-diffraction experiments. 10 A detailed analysis of the observed reflections led Kamimura et al to the conclusion that the distorted nuclear structure of the SP phase in CuGeO 3 should belong to space group Bbmm or Bbcm. 10 A collection of 11 superstructure reflections in the SP phase by neutron diffraction allowed Hirota et al 11 to determine the space group to be Bbcm in accordance with the electron-diffraction results.…”

Crystal Structure of the High Pressure Phase(II) in CuGeO3

“…A large number of investigations concerned with the characterization of its structural and physical properties was done at low temperature and high pressure because of the strong correlation between structural, elastic, and magnetic properties in spin-Peierls transition system [3,4]. Evidence for the lattice dimerization, which is accompanied by the spin-Peierls transition at low temperature, was observed in electron [5], x-ray and neutron diffraction experiments [6±8]. The spin-Peierls transition temperature is strongly pressure dependent and increases from about 14 K at 0.1 MPa to 25 K at 3 GPa [9].…”

Disorder, structured diffuse scattering and the transmissionelectron microscope

“…see e.g. Sato et al, 1962;Honjo et al, 1964;Billingham et al, 1972;de Ridder et al, 1977a, b;Norman et al, 1985;Gomyo et al, 1988;Withers et al, 1989Withers et al, , 1994aKamimura et al, 1994: van Tendeloo et al, 1976Tabira et al, 2000 etc. ) whose reciprocal lattices at one temperature or the other exhibit highly structured (often quite weak) diffuse intensity distributions accompanying the strong Bragg reflections of an underlying average structure (see e.g.…”