Paper Title
Effect of Mechanochemistry on Crystallite Size & Photoluminescence Properties of Matlockites Doped with Samarium Ions at Room Temperature

The mechanochemical synthesis of MFX (M = Ba, Sr; X = Cl, Br, I) systems doped with samarium ions in the trivalent oxidation state is reported. The crystallite size is significantly reduced as a function of milling time when stoichiometric ratios of BaCl2 or SrCl2, BaF2 or SrF2, and SmCl3.6H2O were ball-milled. The MFX:Sm3+ systems crystallize in the tetragonal P4/nmm-D4h space group. The oxidation state of samarium in the different host lattices was investigated using room temperature photoluminescence. In addition, the sample phases were analysed by Rietveld refinements of the XRD patterns. The XRD patterns show that prolonged ball-milling leads to slight contamination with zirconia from the balls and bowls of the shaker mill. This paper demonstrates that small crystallites/particles with relatively narrow size distributions can be obtained by the ball-milling route and the entire class of matlockites doped with RE2+/3+ can be prepared by this facile method. Keywords - Mechanochemical synthesis, Photoluminescence, MeFX: Sm3+