Origin of forbidden reflections in multiferroic Ba${}_2$CoGe${}_2$O${}_7$ by neutron diffraction: Symmetry lowering or Renninger effect?

Andrew Sazonov, Martin Meven, Georg Roth +4

For a symmetry consistent theoretical description of the multiferroic phase of Ba${}_2$CoGe${}_2$O${}_7$ a precise knowledge of its crystal structure is a prerequisite. In our previous s…