Tuning magnetic frustration in bixbyites

Abstract

The cubic bixbyite structure (α-Mn2O3) has a deep history in solid-state chemistry, the first structural solution was completed by Zachariasen and later corrected by Pauling.[1] Related to the fluorite structure with ¼ of the anions removed, these vacancies force the displacement of the remaining anions changing the coordination from cubic to strongly distorted octahedra. Today bixbyites are commonplace in every household found in everything from batteries, TV monitors and touch screens to industry catalysts. The ternary oxide Cu3TeO6 is an ordered bixbyite that has been the focus of intense study due to its interesting magnetic spin-web structure.[2-5] We have synthesized powders and single crystals from the solid solution Cu2.25+3x/4Sb1-xTexO4.75+5x/4, Ga and Mn doped variants. Through single crystal, powder X-ray diffraction (XRD) and neutron diffraction (ND) we have seen that the bixbyite lattice can accommodate for a large variation of dopant pressure through site disorder and defects.[6] K and L-edge X-ray absorption spectroscopy has shown the bixbyite structure will also accommodate a large variation of charged species which when coupled with defects and site disorder manifests itself into interesting frustrated magnetic structures varying from canonical spin-glasses to complex anti-ferromagnetic order.