Enhanced ferroelectric and piezoelectric properties of LaxBi(1−x)FeO3 ceramics studied by impedance spectroscopy
Enhanced ferroelectric and piezoelectric properties of LaxBi(1−x)FeO3 ceramics studied by impedance spectroscopy
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DOI：
10.1016/j.ceramint.2017.05.182
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发表时间：
2017-08
影响因子：
5.2
通讯作者：
Peikui Wang;Y. Pu
中科院分区：
文献类型：
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作者：
Peikui Wang;Y. Pu
多铁性铁酸铋（BiFeO 3，BFO）具有较高的居里温度（TC ≥ 830 °C），如果能够实现铁电性和压电性的增强，将是最有前途的高温铁电和压电材料之一。在本工作中，我们将La（x=0.05-0.30）引入BFO中，改变其晶体结构，得到了增强的菱面体结构。采用微波水热法制备了晶粒细化的高纯LaxBi（1−x）FeO 3（LBFO）粉体，并在微波条件下进行了烧结。压电性能的提高（d33=55- 62 pC·N-1）表明，在一定的掺杂量范围内，La 3+不仅可以稳定菱面体结构，而且可以形成亚稳相，从而产生压电效应。介电性能随频率的变化曲线表明，La 3+掺杂BFO陶瓷的介电常数增加，损耗降低。在不同温度下，由半圆弧在真实的轴（Z）上的截距得到的体电阻（Rb）值随掺杂量的增加而减小。Pr值的增加可能是由于La的引入导致BFO陶瓷的晶体结构发生畸变，形成了更多的偶极子或短程载流子。M-H回线表明，随着La含量的增加，LBFO陶瓷的饱和磁化强度和矫顽力都有所提高。
Multiferroic bismuth ferrite (BiFeO3, BFO) is one of the most promising high-temperature ferroelectric and piezoelectric materials due to a high Curie temperature (TC∼830 °C) if the enhancement of ferroelectricity and piezoelectricity can be realized. In this work, we introduced La (x=0.05–0.30) to BFO to change its crystal structure and obtained an enhanced Rhombohedral structure. The high pure LaxBi(1−x)FeO3(LBFO) powders with refined grain size were prepared by microwave hydrothermal method, then the ceramics were sintered under microwave condition. The enhanced piezoelectric property results (d33=55–62pC·N−1) showed that La3+could not only stable the Rhombohedral structure and form Metastable phase contributing to the piezoelectric effects at a special range of doping contents. The figure of dielectric property versus frequency indicated La3+doped BFO ceramics could increase dielectric constant and reduce the loss. The values of bulk resistance (Rb) obtained from the intercept of semicircular arcs on the real axis (Z) at different temperatures decrease with the increasing of the doping contents. The Princreased which could be ascribed to that the introduction of La could lead to the distortion of the crystal structure of BFO ceramics and the formation of more dipoles or short-range charge carriers. Finally, the M-H loops suggested that the Saturation magnetization and Coercive magnetic field LBFO ceramics was improved with increasing La contents.