%0 Journal Article
%A Sazonov, Andrew
%A Meven, Martin
%A Roth, Georg
%A Georgii, Robert
%A Kézsmárki, István
%A Kocsis, Vilmos
%A Tokunaga, Yusuke
%A Taguchi, Yasujiro
%A Tokura, Yoshinori
%A Hutanu, Vladimir
%T Origin of forbidden reflections in multiferroic Ba$_{2}$CoGe$_{2}$O$_{7}$ by neutron diffraction: symmetry lowering or Renninger effect?
%J Journal of applied crystallography
%V 49
%N 2
%@ 1600-5767
%C Copenhagen
%I Munksgaard
%M FZJ-2016-07019
%P 556 - 560
%D 2016
%X For a symmetry-consistent theoretical description of the multiferroic phase of Ba2CoGe2O7 a precise knowledge of its crystal structure is a prerequisite. In a previous synchrotron X-ray diffraction experiment on multiferroic Ba2CoGe2O7 at room temperature, forbidden reflections were found that favour the tetragonal-to-orthorhombic symmetry lowering of the compound [Hutanu, Sazonov, Murakawa, Tokura, Náfrádi & Chernyshov (2011), Phys. Rev. B, 84, 212101]. Here, the results are reported of room-temperature single-crystal diffraction studies with both hot and cold neutrons to differentiate between genuine symmetry lowering and multiple diffraction (the Renninger effect). A comparison of the experimental multiple diffraction patterns with simulated ones rules out symmetry lowering. Thus, the structural model based on the tetragonal space group P\overline{4}2_{1}m was selected to describe the Ba2CoGe2O7 symmetry at room temperature. The precise structural parameters from neutron diffraction at 300 K are presented and compared with the previous X-ray diffraction results.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000373702000025
%R 10.1107/S1600576716002405
%U https://juser.fz-juelich.de/record/824430