Speaker
Description
Antimony based transition metal oxides have been researched and studied for years due to the interesting semiconductor and photocatalytic properties they exhibit. Whilst most transition metal antimonates (e.g. NiSb$_2$O$_6$, ZnSb$_2$O$_6$, CoSb$_2$O$_6$ etc.) exist in a tetragonal trirutile structure, CuSb$_2$O$_6$ exhibits a slight monoclinic distortion due to Jahn Teller effects dominating the structure. In our research, an investigation was undertaken to investigate how doping Ni into a CuSb$_2$O$_6$ lattice would affect the structure of the material. It is well known that the structure of a material defines it properties, and through a systematic study we seek to understand this relationship within such antimonates.
Both bulk powder and single crystal samples were synthesised for this work, using high temperature sintering and chemical vapour transport respectfully. In the doped powder samples, XAS measurements indicate that some of the Cu ions are being reduced from Cu$^{2+}$ to Cu$^{1+}$ in the structure, reducing the effect of the Jahn Teller distortion and removing the monoclinic distortion. There has also been indication that there may be a potential low temperature phase transition occurring in the NiSb$_2$O$_6$ structure, analysed through a single crystal diffraction across a decreasing temperature range.
