Abstract
Polycrystalline sample of Pb2Bi3SmTi5O18, a member of tungsten–bronze (TB) family, was prepared using a high temperature solid state reaction technique. X-ray diffraction (XRD) analysis indicated the formation of a single phase orthorhombic structure. AC impedance plots were used as a tool to analyse the electrical behaviour of the sample as a function of frequency at different temperatures. The ac impedance studies revealed the presence of grain boundary effect, from 350°C onward. Complex impedance analysis indicated non-Debye type dielectric relaxation. The Nyquist plot showed the negative temperature coefficient of resistance (NTCR) character of Pb2Bi3SmTi5O18. AC conductivity data were used to evaluate the density of states at Fermi level and activation energy of the compound.