The Crystalline and Dielectric Properties of 0.38 (Bi 1-x La x )ScO 3 -0.62PbTiO 3 Ferroelectric Ceramics
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0888-V09-09.1
The Crystalline and Dielectric Properties of 0.38(Bi1-xLax)ScO3-0.62PbTiO3 Ferroelectric Ceramics Yi Chen1, Dejun Lan1, Qiang Chen1, Zhuo Xu2, Xi Yue1, Dingquan Xiao1 and Jianguo Zhu1, * 1 College of Materials Science & Engineering, Sichuan University, Chengdu, 610064, China 2 Electronic Materials Research Laboratory, Xi’an Jiaotong University, Xi’an, 710049,China ABSTRACT To investigate the effects of partially substitution of lanthanum for bismuth in the BiScO3-PbTiO3 (BSPT) ceramics, the 0.38(Bi1-xLax)ScO3-0.62PbTiO3 (BLSPTx) ceramics were prepared by using conventional solid state process. It was found that the partial replacement of lanthanum for bismuth do not affects the crystalline structure of the BSPT ceramics. With increasing of the lanthanum content, the grains of BLSPTx ceramics grown much bigger than those of BSPT ceramics when BLSPTx and BSPT ceramics were sintered at the same temperature. The temperature dependence of dielectric permittivity of BLSPTx ceramics shows that the Curie temperature (Tc) shifts toward lower temperature with the increasing of lanthanum content, and the BLSPTx samples for x=0.02 show the highest value of the dielectric constant at Tc. INTRODUCTION The traditional piezoelectric materials based on Pb(Zr,Ti)O3 (PZT) system are widely used in electronics applications such as filters, sensors and actuators[1,2]. There are a number of piezoelectric devices in automotive, aerospace, and related industrial applications. Both of the automotive and aerospace industries have expressed the need for piezoelectric devices which can work at higher temperatures than currently available piezoelectric devices [3]. In such applications, new piezoelectric materials with high Curie temperatures (TC) and good piezoelectric properties are essential to these systems. As recently reported[4~9], bismuth-based perovskite system (1-x)BiScO3-xPbTiO3 (BSPT) ceramics were found to possess a Curie temperature higher than 450℃, which is more than 100℃ higher than commercial PZT ceramics, and had excellent piezoelectric properties near the morphotropic phase boundary (MPB) composition. The maximum value of piezoelectric coefficient d33 of BSPT ceramics is about 460pC/N, which is comparable to that of PZT. These properties suggest that the BSPT system is a kind of attractive candidate materials for applications requiring high temperature and temperature stable properties. To optimize properties of the BSPT system, Eitel [10] used La3+ as donor dopant to partially substitute for Pb2+ on the A-site of perovskite structure, and the charge difference of lanthanum and lead on the A-site was accommodated through formation of B-site vacancies. When sintered under the same temperature, lanthanum doped BSPT samples exhibited much smaller grain sizes, and showed no improvement of the dielectric and piezoelectric properties. And when La doped BSPT ceramics were sintered at higher temperature to achieve grain size similar to undoped *Corresponding author: E-mail:[email protected]
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BSPT cera
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