Shi Yunjing, Dong Xiaoyu, Zhao Kunyu, Yang Weiwei, Zhu Kun, Hu Rui, Zeng Huarong, Shen Bo, Zhai Jiwei
Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China.
Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China.
ACS Appl Mater Interfaces. 2021 Mar 31;13(12):14385-14393. doi: 10.1021/acsami.1c00790. Epub 2021 Mar 19.
Herein, the second-order Jahn-Teller effect was applied to the design of the bismuth ferrite-based ceramics. A large distortion of an electron structure arranged along the axis and an asymmetric distribution of charge density were calculated in 0.80(0.725BiFeO-0.275BaTiO)-0.20PT (0.20 PT) based on the density functional theory, indicating good ferro/piezoelectric properties. The top experimental polarization of 36.89 μC/cm, optimal value of 258 pC/N measured at room temperature, and ultrahigh value of 303 pC/N measured at 370 °C were obtained at 0.20 PT, thereby further confirming the calculations. Furthermore, a high Curie point of 488 °C, as well as outstanding temperature stability ranging from room temperature to 430 °C of the 0.20 PT ceramic was observed. The domain of the 0.20 PT exhibited greater order and smaller size, resulting in easy switching when applying voltage. The distorted electron structure, plumb grains, ordered and easily switchable domains, and coexistences of tetragonal (T) and rhombohedral (R) phases contributed to the large piezoelectric constant of the 0.2 PT ceramic. BFBT-PT ceramics are potentially promising for high-temperature piezoelectric field applications.
在此，二阶 Jahn-Teller 效应被应用于铋铁氧体基陶瓷的设计。基于密度泛函理论，计算出在 0.80(0.725BiFeO₃ - 0.275BaTiO₃)-0.20PT（0.20PT）中沿 c 轴排列的电子结构发生了较大畸变以及电荷密度的不对称分布，这表明其具有良好的铁电/压电性能。在 0.20PT 处获得了室温下 36.89 μC/cm 的最高实验极化强度、258 pC/N 的最佳 d₃₃ 值以及 370 °C 下 303 pC/N 的超高 d₃₃ 值，从而进一步证实了计算结果。此外，观察到 0.20PT 陶瓷具有 488 °C 的高居里点以及从室温到 430 °C 的出色温度稳定性。0.20PT 的畴显示出更大的有序性和更小的尺寸，在施加电压时易于切换。畸变的电子结构、铅晶粒、有序且易于切换的畴以及四方（T）相和菱方（R）相的共存促成了 0.2PT 陶瓷的大压电常数。BFBT-PT 陶瓷在高温压电场应用方面具有潜在的广阔前景。
