Enhanced electrocaloric effect in lead free Ba0.90Sr0.10Ti1-3x/4FexO3 ceramics.

Polycrystalline ceramic samples with compositional formula Ba 0 · 90 Sr 0 · 10 Ti 1-3x/4 Fe x O 3 (x = 0, 0.01 and 0.015) 'BTSF' were prepared by the conventional solid state reaction method. The phase confirmation was done by using X-ray diffraction 'XRD' technique. Tetragonality 'c/a' was found to be decreased with Fe3+ substitution. Dielectric constant 'ε' and tangent loss 'tanδ' was measured as a function of temperature at different frequencies (1, 10, 40, 80 and 100 kHz). The value of ε and tanδ at 30 °C for BTSF0 sample was found to be 2300 and 4.5% (at 100 kHz), whereas for BTSF2 sample it was 3170 and 2.3% (at 100 kHz). The dielectric results indicate the prepared samples can be the potential candidates for capacitive applications. The P-E hysteresis loops for all samples were recorded at different temperature. The remnant polarization 'P r ' and coercive field 'E c ' was found to be decreased with an increase in temperature for all the samples. Electrocaloric effect 'ECE' was observed in BTSF2 sample. The value of ΔT max was found to be 1.06 K at 25 kV/cm, and the value of the electrocaloric coefficient § max was found to be 0.0424 K cm kV−1. The high value of § max implies that BTSF2 ceramics can be used in potential applications like future solid-state refrigeration technologies. • Tetragonality of BST ceramics decreases with increase in Fe-content. • Dielectric constant and tangent loss improves with an increase in Fe-content. • A large value of adiabatic ΔT = 1.06 K was observed in BTSF2 sample. • The electrocaloric strength is very large (0. 0424 K cm kV-1) in BTSF2 sample. [ABSTRACT FROM AUTHOR]