Preparation, characterization and electrical conductivity studies of nanocrystalline La doped BaMoO4

Different compositions of scheelite type nanocrystalline La doped BaMoO₄ [Ba_1−xLa_xMoO_4+x/2, where x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5] samples were prepared by acrylamide assisted sol-gel combustion process. Dried gels prepared at 60 °C were heated at different temperatures and characterized using TG/DTA, XRD, FTIR and SEM-EDX techniques. From XRD patterns, crystalline phases for La doped BaMoO₄ samples were confirmed and their average crystallite sizes were calculated using Scherrer's formula and it was found to be less than 80 nm. Structure and thermal behavior of scheelite type nanocrystalline La doped BaMoO₄ samples were identified respectively using FTIR and TG/DTA measurements. Microstructure and existence of O, La, Ba and Mo elements in the La doped BaMoO₄ samples were obtained from SEM-EDX and HRTEMtechniques. The ‘d’ spacing values were obtained for different (h k l) planes and were well matched with the standard BaMoO₄. (h k l) values for different directions of planes were assigned for the observed HRTEM images and were matched with standard BaMoO₄. Grain and grain boundary conductivities were evaluated by analyzing the impedance data, using the Winfit software, measured at different temperatures.