Studies of dielectric, pyroelectric and conduction mechanism of Sr3Ta2O8

The current research work reports on structural, dielectric, pyroelectric and conduction properties of strontium orthotantalate, prepared by using a high-temperature solid-state reaction technique. Preliminary x-rays structural study of the material confirms the formation of a single-phase compound with trigonal crystal structure. The microstructure of gold-coated pellet sample recorded by scanning electron microscopy (SEM) shows well-defined and homogeneously distributed grains. Detailed studies of dielectric parameters (εr and tan δ) of the compound as a function of temperature at some selected frequencies reveal that these parameters are invariant in a wide range of frequency and temperature (room temperature to about 400 °C). Studies of pyroelectric properties reveal that the materials have reasonably high figure of merit useful for fabrication of pyroelectric detector. The ac conductivity spectra show a typical-signature of an ionic conducting system, and are found to obey Jonscherʹs universal power law. The low leakage current and negative temperature coefficient of resistance (NTCR) behavior of the sample have been verified from J~E plots. The nature of variation of dc conductivity with temperature confirms the Arrhenius and NTCR behavior in the material.