A local distortion of polyhedra in the novel chromium doped mullite-type bismuth ferrite Bi-2(CrxFe1-x)(4)O-9

Abstract

Chromium doped mullite-type ferrite, Bi2(Cr0.1Fe0.9)4O9, is synthesized for the first time by a combined mechanochemical/thermal route. The microstructure of the as-prepared material on the long-range and local atomic scales, revealed by X-ray diffraction and 57Fe Mössbauer spectroscopy, respectively, is found to be quite different from that reported previously. It is shown that the presence of Cr3+ cations in octahedral sites of the orthorhombic structure causes a local distortion of polyhedra in the material. Quantitative information on both the cation distribution and the bond lengths provided is discussed in relation to the derived hyperfine parameters.