Investigating the Structure of La$_{2}$CuGa$_{12}$, Using Neutron Powder Diffraction

Single crystals of a new phase, La$_{2}$CuGa$_{12}$, have been synthesized using flux growth. Preliminary single crystal X-ray diffraction results suggest La$_{2}$CuGa$_{12}$ to be isostructural to Ce$_{2}$PdGa$_{12 }$and crystallize in the $P$4/\textit{nbm} space group with lattice parameters of $a \quad \sim $ 6.179 {\AA} and $c \quad \sim $ 15.384 {\AA}. Residual electron density, which was observed in the Fourier difference map of the single crystal X-ray diffraction data, and the observation of satellite peaks in the data are indicative of the possibility of statistical disorder in La$_{2}$CuGa$_{12}$. In addition, unusual behavior of thermal parameters for an additional Ga position is observed in the X-ray diffraction data of La$_{2}$CuGa$_{12}$. Although a preliminary model has been constructed using single crystal X-ray diffraction experiments, due to the two electron difference between $^{29}$Cu and $^{31}$Ga, neutron powder diffraction experiments may be a more suitable probe in accurately determining the structure and site occupancy of the additional Ga atom in La$_{2}$CuGa$_{12}$. We have employed neutron powder diffraction (BT-1) to investigate the structure in the phase, La$_{2}$CuGa$_{12}$.