Structural, dielectric and electrical properties of Li2Pb2La2W2Ti4Nb4O30 ceramic

Li2Pb2La2W2Ti4Nb4O30 complex ferroelectric oxide was prepared by using a high-temperature solid-state reaction method (calcination temperature, ~1100 °C and sintering temperature, ~1150 °C). Room temperature preliminary structural analysis shows formation of a single-phase compound. The nature of microstructure (i.e. grain distribution, presence of voids, grain size, etc) recorded using scanning electron microscope (SEM) clearly suggests the formation of high quality and density of pellet samples. Studies of temperature dependence of dielectric constant, tangent loss and polarization show the existence of ferroelectric phase transition in the material at high temperature (307 °C). Detailed studies of temperature dependence of electrical parameters (i.e. impedance (400−475 °C), modulus, conductivity, etc) of the material clearly suggest a strong correlation between its microstructure (i.e. bulk, grain boundary, etc) and electrical properties. The nature of temperature variation of d.c. conductivity showed an Arrhenius behaviour of the material. A signature of ionic conductivity in the material was observed in its a.c. conductivity spectrum. The nature of frequency dependence of a.c. conductivity of the material can be explained by Jonscher’s universal power law. Electrical transport properties of the material show existence of non-exponential type of conductivity relaxation.