Structural, dielectric and electrocaloric properties in lead-free Zr-doped Ba_0.8Ca_0.2TiO₃ solid solution

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• 作者：B. Asbani^a ; ^b ; Y. Gagou^a ; ^{yaovi.gagou@u-picardie.fr" class="auth_mail" title="E-mail the corresponding author} ; J.-L. Dellis^a ; A. Lahmar^a ; M. Amjoud^b ; D. Mezzane^b ; Z. Kutnjak^c ; M. El Marssi^a
• 关键词：A. Ferroelectrics ; B. BCTZ ceramics ; C. Perovskite oxide ; D. Electrocaloric ; E. X-ray diffraction
• 刊名：Solid State Communications
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：237-238
• 期：Complete
• 页码：49-54
• 全文大小：3033 K

文摘

We investigate in the present work the additional data points (x=0.02, 0.06 and 0.08) to the previous reported paper (Asbani et al., 2015) [21] that sufficiently enrich to understand the EC properties and underlying phase diagram of the lead-free Ba_0.8Ca_0.2Ti_(1−x)Zr_xO₃ (xBCTZ) system. X-ray diffraction analysis performed at room temperature, confirms a continuous tetragonal solid solution with P4mm (No. 99) space group that evolved to pseudo-cubic symmetry for the high Zr-content compounds. Ferroelectric and paraelectric behaviors were highlighted using P–E hysteresis data versus temperature. Phase transition was confirmed by dielectric permittivity measurements versus temperature showing a decrease of the Curie temperature when Zr-content increases. From P–E hysteresis recording the electrocaloric temperature change (ΔT) was calculated that ranged in between 0.12 and 0.27 K and the electrocaloric responsivity (ξ) in 0.15 to 0.34×10⁻⁶ K·m/V under 7.95 kV/cm applied electric field. The zero-field entropy is compared to electrocaloric isothermal entropy to estimate the extent the EC is being under-driven.