Structural and electrical studies of Ba5LaTi3V7O30 compound

The ferroelectric ceramic Ba5LaTi3V7O30 has been synthesized by solid-state reaction technique. Preliminary X-ray structural analysis confirmed a single-phase formation (orthorhombic crystal system) of the compound. Surface morphology of the compound was studied by scanning electron microscopy (SEM). Detailed studies of electrical properties (i.e., dielectric constant, loss tangent, ac and dc conductivity) as a function of temperature (RT - 773 K) at four different frequencies, 1 kHz, 10 kHz, 100 kHz and 1 MHz show ferroelectric—paraelectric phase transition of the compound. The impedance spectra show two distinctly separated regions in wide temperature range corresponding to grain boundary and grain interior contributions. The activation energy has been evaluated from ac conductivity and dc conductivity following Arrhenius equation is 0.15 eV at 1 MHz and 0.28 eV, respectively. The temperature dependence of electrical conductivity shows that the conductivity increases with increase in temperature suggesting that the compounds have a negative temperature coefficient of resistance (NTCR) behaviour. The conductivity pattern shows that it is strongly frequency dependent and obeys Jonscher’s power relation.