Dielectric and Pyroelectric Studies of Tungsten—Bronze Structured Ba5SmTi3Nb7O30 Ferroelectric Ceramics

Abstract

In the present work, sample of composition Ba 5 SmTi 3 Nb 7 O 30 was prepared by solid-state reaction method. X-ray diffraction (XRD) analysis reveals the formation of single-phase compound with an orthorhombic structure. The grain morphology of the sample has been investigated by scanning electron microscopy. Dielectric properties of the compound have been studied as a function of temperature and frequency. The variation of dielectric constant (ϵ′r) with temperature at different frequencies shows that the compound has a dielectric anomaly of ferroelectric to paraelectric type at 170°C, and exhibits non-relaxor kind of diffuse phase transition. At different frequencies, the variation of dielectric loss (tan δ) with temperature shows at lower temperatures the loss is almost constant and increases sharply at higher temperatures. The frequency dependence of dielectric constant and loss show a decreasing trend upto 10 kHz and beyond this frequency they remain almost constant. The variation of pyroelectric coefficient with temperature is reported in the present work. Pyroelectric figure of merit have been calculated from the pyroelectric coefficients.