Role of cadmium on the phase transitions and electrical properties of BaTiO₃ ceramics

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• 作者：Ruihao Yuan^a ; Prasanna V. Balachandran^b ; Deqing Xue^a ; Yumei Zhou^a ; Xiangdong Ding^a ; Jun Sun^a ; Turab Lookman^b ; Dezhen Xue^a ; ^{xuedezhen@mail.xjtu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ceramics ; Cd2+ ; MPB ; Piezoelectric ; Ferroelectric ; Lead-free
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1114-1120
• 全文大小：1466 K

文摘

The search for high piezoelectric and electromechanical properties near morphotropic phase boundaries (MPB) in lead-free ceramics has attracted considerable interest. The MPB can be obtained in the composition-temperature phase diagram by combining stabilized rhombohedral (R) and tetragonal (T) ends, which possess cubic (C) to R or C to T transitions, respectively. The R-end is usually realized by doping ions Zr⁴⁺${\mathrm{Zr}}^{4+}$, Hf⁴⁺${\mathrm{Hf}}^{4+}$ or Sn⁴⁺${\mathrm{Sn}}^{4+}$ at the Ti⁴⁺${\mathrm{Ti}}^{4+}$ site, whereas the T-end can be generated by Ca²⁺${\mathrm{Ca}}^{2+}$ doped at the Ba²⁺${\mathrm{Ba}}^{2+}$ site of BaTiO₃${\mathrm{BaTiO}}_3$. Our recent computational work (Phys. Rev. B. 93, 144111, 2016) showed that Cd²⁺${\mathrm{Cd}}^{2+}$ doped BaTiO₃${\mathrm{BaTiO}}_3$ can be considered as a potential T-end. In the present study, we synthesized (Ba_1−xCd_x)TiO₃$({\mathrm{Ba}}_{1-x}{\mathrm{Cd}}_x){\mathrm{TiO}}_3$ ceramics to investigate the effects of Cd²⁺${\mathrm{Cd}}^{2+}$ on the phase transition, dielectric, ferroelectric and piezoelectric properties of the ceramics. Although our results show that Cd²⁺${\mathrm{Cd}}^{2+}$ fails to stabilize the T phase, i.e., the transition temperatures vary little with Cd²⁺${\mathrm{Cd}}^{2+}$ concentration, the electrical properties are found to be optimized for Cd²⁺${\mathrm{Cd}}^{2+}$% of 5%. The optimization of the properties is related to the microstructural features including grain size and sample density.