A new ferroelectric oxide Li2Pb2Pr2W2Ti4Nb4O30: Synthesis and characterization

A new ferroelectric oxide (Li2Pb2Pr2W2Ti4Nb4O30) of tungsten bronze structural family has been synthesized by a solid-state reaction (mixed-oxide) route at high temperature (∼1100 °C). X-ray structural analysis with room temperature diffraction data confirms the formation of a single phase compound. The scanning electron microscopic (SEM) texture of the surface of material sample exhibits a uniform grain distribution with a few small voids suggesting the formation of high-density pellet sample. Detailed studies of dielectric constant, tangent loss and polarization with temperature and frequency confirmed the existence of ferroelectric properties in the material with transition temperature much above room temperature. Study of electrical properties (impedance, modulus, conductivity, etc.) of the material exhibits a strong correlation between its micro-structure (i.e., bulk, grain boundary, etc.) and electrical parameters. The nature of variation of dc conductivity with temperature confirms the Arrhenius behavior of the material. The presence of ionic conductivity in the material was observed in its ac conductivity spectrum. Study of frequency dependence of ac conductivity suggests that the material obeys Jonscher's universal power law. The experimental electrical transport properties of the material clearly exhibit the existence of non-exponential-type of conductivity relaxation.

► The tungsten–bronze material has high dielectric constant at room temperature. ► It has good ferroelectric properties as observed from both from phase transition and hysteresis loop. ► The material has good semiconducting properties as calculated from dc conductivity and ac conductivity calculation.