Lei Liu,Fangyi Yin,Guiyuan Zhao,Limei Zheng,Xiuwei Fu,Zhitai Jia,Xutang Tao
B 0 . 7 7 Ca 0 . 2 3 TiO 3 (BCT) single crystal has been widely studied as a promising lead-free ferroelectric material. In this work, high-quality BCT crystal was successfully grown by the Czochralski (CZ) method. The as-grown crystal is crack-free and shows black coloration. It possesses a high dielectric stability over a wide temperature range, while the dielectric loss is rather small below 90 ∘ C. Furthermore, it possesses excellent ferroelectric properties with residual polarization strength ( P r ) and coercive field ( E c ) of 17.93 μ C/cm 2 and 8.47 kV/cm, respectively. Besides, BCT crystal shows large electromechanical coupling factors, with k t , k 3 1 , k 3 3 and k 1 5 of 0.535, 0.254, 0.714 and 0.721, respectively. The piezoelectric coefficients d 3 1 , d 3 3 and d 1 5 are measured to be − 36.5, 130 and 246 pC/N, respectively.
Luhui Zhou,Peng Du,Quan Zhang,Jiujun Zhu,Yafei Hou,Laihui Luo,Weiping Li
The Pr 3+ -doped Ba 0·77 Ca 0·23 TiO 3 ferroelectric ceramics , which were sintered by means of a high-temperature solid-state reaction technology, were prepared. The Rietveld X-ray diffraction refinement and Raman spectrum proved that the resultant compounds had tetragonal phase. With the addition of Pr 3+ ions, the highest remanent polarization of the resultant ceramics was nearly two times higher than that of the pure Ba 0·77 Ca 0·23 TiO 3 ceramics. With the aid of a theoretical calculation based on the temperature-dependent dielectric constant, it is found that the synthesized compounds pertained to the relaxor-like ferroelectrics . Furthermore, through the piezoresponse force microscopy technique, the effect of Pr 3+ ions doping on the domain structure of the Ba 0·77 Ca 0·23 TiO 3 ferroelectric ceramics was studied. Additionally, the prepared ferroelectric ceramics can exhibited the characteristic emissions of Pr 3+ ions when excited by 450 nm light. The strongest emission intensity was achieved when the dopant content was 0.5 mol% and the dipole-quadrupole interaction contributed to the relevant concentration quenching mechanism.
危险品化学品经营许可证（带存储）