Nanostructured BaTi_1-xSn_xO₃ ferroelectric materials for electrocaloric applications and energy performance

Abstract : Nanostructured BaTi_1-xSn_xO₃ (x = 0, 0.05 & 0.075) were successfully synthesized using the modified Pechini processing method. The phase purity and symmetry were examined by X-ray diffraction and Raman spectroscopy. Tetragonal symmetry was obtained for BaTiO₃ (BT) while orthorhombic symmetry for Sn doped BT. BT exhibits an up-shift of the Curie temperature towards high temperatures (TC = 139 °C). In contrast, a down-shift was recorded for Sn doped BT. Then, indirect electrocaloric (EC) adiabatic temperature change ΔT and the energy storage performances were determined based on ferroelectric hysteresis loops. Interestingly, large EC responsivity of ΔT/ΔE = 0.81 × 10−6 K m/V was obtained for the BT accompanied with a moderate stored energy of 23 mJ/cm3 but with a high energy efficiency of 67%. The incorporation of Sn in BT was found to broaden the EC responsivity and to improve the energy efficiency up to 90%, recorded for the 5% Sn doped BT.