Thermal energy conversion and temperature-dependent dynamic hysteresis analysis for Ba0.85Ca0.15Ti0.9-xFexZr0.1O3 ceramics

Temperature-dependent ferroelectric behavior in Ba0.85Ca0.15Ti0.9-xFexZr0.1O3 (BCT-BZT-Fe) (x = 0%, 0.5%, 1%) has been investigated. Olsen cycle is used to estimate the thermal energy conversion potential in the compositions under study. The maximum energy conversion density of 305 kJ/m(3) per cycle is obtained for BCT-BZT-Fe (0.5% Fe content) when the cycle is operated between 30 and 110 degrees C and an electric field of 0-3 MV/m. The obtained energy density is very high for small electric field and temperature gradient as compared to other lead-free ferroelectric materials. A comparison table of previously reported Olsen cycle-based energy conversion in bulk ferroelectric ceramics is presented. Temperature also affects the hysteresis parameters, therefore, scaling relations for coercive field (Er) and remnant polarization (Pr) as a function of temperature (T) were also observed. The power-law exponents are obtained for all hysteresis parameters in the compositions under study. The scaling relations are found as E, a T-0.658 Ec oc T-0.687 and E-c proportional to T-0.717 for 0%, 0.5% and 1% Fe, respectively. Similarly, P-r proportional to T-1.59, P-r proportional to T-1.65 and P-r proportional to T-1.85 are for 0%, 0.5% and 1% Fe, respectively. Additionally, back-switching polarization (P-bc) behavior as a function of temperature is estimated by well-described Arrhenius law to evaluate the average activation energy for all the compositions. (C) 2016 The Ceramic Society of Japan and the Korean Ceramic Society. Production and hosting by Elsevier B.V.