Electrocaloric effect and temperature dependent scaling behaviour of dynamic ferroelectric hysteresis studies on modified BTO.

The large electrocaloric effect associated with the ferroelectric-relaxor and ferroelectric-paraelectric phase transition, and various temperature dependent scaling behaviours on A-site modified BaTiO 3 (Ba 1-x Sr x TiO 3 , x = 0.00, 0.10, 0.20, and 0.25) have been reported in this article. The compositionally induced relaxor behaviour with diffuse phase transition has been reported. The Rietveld refinement of XRD patterns reveals that all the samples crystallize to the P4mm space group. Raman spectra analysis at room temperature supports the XRD patterns analysis. The diffuse phase transition behaviour of the prepared sample has been confirmed by estimating the diffuse phase parameter (γ = 1.444 ± 0.003) from the temperature variation dielectric plot. A large adiabatic temperature change (Δ T) of 0.278 K and isothermal entropy change (Δ S) of 0.494 J/kgK have been observed for the sample x = 0.20 (Ba 0.8 Sr 0.2 TiO 3) at 338 K. The temperature dependent scaling relation for remnant polarization (P r), coercive field (E c), and hysteresis area < A > are found to be P r ∝ T − 1.009 , E c ∝ T − 1.890 and < A > ∝ T − 1.169 , respectively. The present comprehensive studies on A-site modified BaTiO 3 illustrate the electrocaloric cooling efficiency of this material. • Significant adiabatic temperature change (Δ T) of 0.278 K on Ba 0.8 Sr 0.2 TiO 3. • Significant isothermal entropy change (Δ S) of 0.494 J/kg K on Ba 0.8 Sr 0.2 TiO 3. • Polar-nano region (Relaxor ferroelectric signature) near the room temperature. • Diffuse phase parameter (γ =1.444) reveals the diffuse phase transition behaviour of Ba 0.8 Sr 0.2 TiO 3. • The scaling relations are P r ∝ T − 1.009 , E c ∝ T − 1.890 , and < A > ∝ T − 1.169 . [ABSTRACT FROM AUTHOR]