Structural, Optical, and Electrical Characterization of Yttrium-Substituted BiFeO3 Ceramics Prepared by Mechanical Activation

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• 作者：Antonio Perej贸n ; Eva Gil-Gonz谩lez ; Pedro E. S谩nchez-Jim茅nez ; Jos茅 M. Criado ; Luis A. P茅rez-Maqueda
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：October 19, 2015
• 年：2015
• 卷：54
• 期：20
• 页码：9876-9884
• 全文大小：540K
• ISSN：1520-510X

文摘

Ceramics of Bi_1鈥?i>xY_xFeO₃ solid solutions (x = 0.02, 0.07, and 0.10) have been prepared by mechanical activation followed by sintering. The effect of yttrium content on the structural, electrical, and optical properties of the materials has been studied. Thus, single-phase solid solutions with rhombohedral R3c structure have been achieved for x = 0.02 and 0.07, while for x = 0.10 the main R3c phase has been detected together with a small amount of the orthorhombic Pbnm phase. Multiferroic properties of the samples, studied by differential scanning calorimetry (DSC), showed that both T_N and T_C (temperatures of the antiferromagnetic鈥損aramagnetic and ferroelectric鈥損araelectric transitions, respectively) decrease with increasing yttrium content. The nature of the ferroelectric鈥損araelectric transition has been studied by temperature-dependent X-ray diffraction (XRD), which revealed rhombohedral R3c to orthorhombic Pbnm phase transitions for x = 0.07 and 0.10. On the other hand, for x = 0.02 the high-temperature phase was indexed as Pnma. Optical properties of the samples, as studied by diffuse reflectance spectroscopy, showed low optical band gap that decreases with increasing yttrium content. Prepared ceramics were highly insulating at room temperature and electrically homogeneous, as assayed by impedance spectroscopy, and the conductivity increased with x.