Structural, microstructural and electrical studies of La and Cu doped BaTiO3 ceramics

The polycrystalline samples of Ba0.92La0.08Ti1-xCuxO3 (x = 0.0, 0.02, 0.04, 0.06) were prepared by a standard high-temperature solid-state reaction method. X-ray diffraction studies at room temperature confirmed the formation of a single-phase polycrystalline compound with tetragonal (x = 0.0, 0.02) and orthorhombic (x = 0.04, 0.06) crystal structure. Scanning electron micrographs also suggest polycrystalline microstructure with the grains of unequal size distributed throughout the pellet sample. Scanning electron micrographs also suggest polycrystalline microstructure with the grains distributed throughout the pellet samples uniformly. Dielectric studies indicate ferroelectric-paraelectric phase transition with a clear shift in the Curie temperature (T-c) of BaTiO3 towards low temperature on doping. Complex impedance spectroscopy analysis indicated, negative temperature coefficient of resistance (NTCR) type behavior irrespective of doping. Conductivity and relaxation properties appear to be thermally activated process and their values suggest that both the conductivity and relaxation species are identical. (C) 2009 Elsevier B.V. All rights reserved.