Direct electrocaloric, structural, dielectric, and electric properties of lead-free ferroelectric material Ba0.9Sr0.1Ti1-xSnxO3 synthesized by semi-wet method.

By using the semi-wet synthesis method, lead-free ferroelectric materials Ba 0.9 Sr 0.1 Ti 1-x Sn x O 3 with x = 0, 0.02, 0.05, and 0.10 (abbreviated as BSTS) were prepared and their structural, electric and electrocaloric properties were investigated. The X-ray diffraction (XRD) patterns show that the samples calcined at 950 °C have well crystallized into perovskite structure suggesting the substitution of Ti4+ by Sn4+ in BST lattice. With increasing content of Sn, the enhancement of the dielectric permittivity was observed for (0 ≤ x ≤ 0.05) and the ferroelectric transition temperature (T C) was found to shift towards the room temperature (T C = 20 °C for x = 0.10). Direct measurements of the electrocaloric effect (ECE) were performed on all samples by using the high-resolution calorimeter. It is found that Ba 0.9 Sr 0.1 Ti 0.95 Sn 0.05 O 3 exhibits a high ECE temperature change of ΔT EC = 0.188 K at an applied electric field of only 7 kV/cm. Impedance spectrum analysis of all the samples performed in the temperature range of 300–360 °C reveals the existence of two relaxation contributions related to the grain and grain boundaries that are well separated in frequency. Activation energies of conduction and relaxation processes were deduced for both contributions in order to determine the conduction mechanism of the studied compositions. • Semi-wet synthesis method is used to prepare the ferroelectric Ba 0.9 Sr 0.1 Ti 1-x Sn x O 3 (BSTS) with x = 0, 0.02, 0.05, and 0.10. • This work shows the effect of Sn on electrocaloric, structural, dielectric and electric of BSTS. • Direct electrocaloric measurements show that BSTS (x = 0.05) exhibits the highest value of EC responsivity (ξ = 0.027 K cm/kV). • Enhancement of dielectric permittivity is observed for (0 ≤ x ≤ 0.05). • Impedance spectroscopy shows that the conduction and relaxation processes can be described by the same activated mechanism. [ABSTRACT FROM AUTHOR]