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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/m3 per cycle is obtained for BCT-BZT-Fe (0.5% Fe content) when the cycle is operated between 30 and 110 °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 (Ec) 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 Ec ∝ T−0.658, Ec ∝ T−0.687 and Ec ∝ T−0.717 for 0%, 0.5% and 1% Fe, respectively. Similarly, Pr ∝ T−1.59, Pr ∝ T−1.65 and Pr ∝ T−1.85 are for 0%, 0.5% and 1% Fe, respectively. Additionally, back-switching polarization (Pbc) behavior as a function of temperature is estimated by well-described Arrhenius law to evaluate the average activation energy for all the compositions.

This paper deals with a study of Ba0.85Ca0.15−xSrxTi0.9Zr0.1O3 (BCT-BZT-Sr) (x = 0%, 5%, 10% and 15%) polycrystalline ceramics for thermal energy conversion applications using the Olsen cycle. A maximum energy conversion density of 108 kJ/m3 was observed in pristine BCT-BZT for cycle operating at 30–90 °C and 0–20 kV/cm. Moreover, the samples with Sr contents (x) of 5%, 10% and 15% display an energy conversion density of 179 kJ/m3, 149 kJ/m3 and 200 kJ/m3, respectively. The Sr addition almost double the energy conversion over the pristine sample under the similar conditions. Also, the temperature (T)-dependent dynamic hysteresis scaling relations for coercive field (EC) and remnant polarization (Pr) were systematically investigated. The power-law scaling exponents are obtained for EC versus T as EC ∝ T−0.65, EC ∝ T−0.61, EC ∝ T−0.56 and EC ∝ T−0.63 for the samples with Sr contents of 0%, 5%, 10% and 15%, respectively. Similarly, the scaling relations for Pr are Pr ∝ T−1.59, Pr ∝ T−1.59, Pr ∝ T−1.36 and Pr ∝ T−1.32 for the samples with Sr contents of 0%, 5%, 10% and 15%, respectively.

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/m3 per cycle is obtained for BCT-BZT-Fe (0.5% Fe content) when the cycle is operated between 30 and 110 °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 (Ec) 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 Ec ∝ T−0.658, Ec ∝ T−0.687 and Ec ∝ T−0.717 for 0%, 0.5% and 1% Fe, respectively. Similarly, Pr ∝ T−1.59, Pr ∝ T−1.65 and Pr ∝ T−1.85 are for 0%, 0.5% and 1% Fe, respectively. Additionally, back-switching polarization (Pbc) behavior as a function of temperature is estimated by well-described Arrhenius law to evaluate the average activation energy for all the compositions. [ABSTRACT FROM AUTHOR]

Bi4Ti3O12‐based thin films of a/b‐axes orientation grown on standard‐type Pt/Ti/SiO2/Si substrates are desirable for designing reliable ferroelectric devices. Herein, a/b‐axes‐oriented and randomly oriented Bi4Ti3O12 thin films are deposited on Pt/Ti/SiO2/Si through a sol–gel process. As expected, the a/b‐axes‐oriented films show a higher remnant polarization than that of randomly oriented films. The characteristic time τ of domain reversal in 74% a/b‐axes‐oriented Bi4Ti3O12 films is 1.1 ms, notably shorter than that (τ > 2.5 ms) for randomly oriented films. The dynamic hysteresis scaling relations of the randomly oriented 56% and 74% a/b‐axes‐oriented Bi4Ti3O12 films take the forms of ⟨A⟩ ∝ f−0.106E01.667, ⟨A⟩ ∝ f−0.035E00.952, and ⟨A⟩ ∝ f−0.026E00.600, respectively. The difference indicates that domain reversal in Bi4Ti3O12 films of predominant a/b‐axes orientation exhibits higher stability compared with randomly oriented Bi4Ti3O12 films under varying electric fields E(E0, f). The enhancing speed and stability of polarization reversal in predominantly a/b‐axes‐oriented Bi4Ti3O12 films can be understood in terms of their layered‐perovskite structure, large columnar grains, oxygen vacancies mobility, domain states, and polarization switching mechanism. [ABSTRACT FROM AUTHOR]