Studies of structural, dielectric, and electrical properties of polycrystalline barium bismuth tungstate for thermistor application

In this communication, preliminary investigation of structural and detailed analysis of electrical proprties of a new barium bismuth tungstate of a chemical composition Ba3Bi2WO9, produced via a standard high-temperature solid-state reaction method, is presented. The basic crystal structure of the compound is monoclinic (a = 8.4621 angstrom, b = 6.7358 angstrom, c = 6.9064 angstrom and beta = 109.94 degrees). The homogeneous distribution of grains (average grain size = 1.717 mu m) is studied via surface morphology demonstrating the feasibility of fabricating a high-density sample under experimental conditions. This compound shows ferroelectric and related properties, which have been experimentally verified by examination of the frequency-temperature dependence of capacitance, impedance, and other related behaviors. The variation of ac conductivity of the material under alternating current varies according to Jonscher's universal power law. The ferroelectric property of the material (Pr = 0.331C/cm2, Ec = 0.207 kV/cm) is demonstrated by the electric field-dependent polarisation (P-E loop) study. The temperature dependence of resistance yields a thermistor constant (beta) and temperature coefficient of resistance (TCR), which may be useful for fabricating thermistor-based device applications.