Hole-pinned defect-dipoles induced colossal permittivity in Bi doped SrTiO₃ ceramics with Sr deficiency

Yulong Qiao¹，Weili Li^1,2，Yulei Zhang¹，Lu Jing¹，Chang Gao¹，Wenping Cao³，Dan Xu⁴，Weidong Fei^1,5

1. School of Materials Science and Engineering, Harbin Institute of Technology2. National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology3. School of Light Industry, Harbin University of Commerce4. Key Laboratory of Quantum Manipulation & Control of Heilongjiang Province, Harbin University of Science and Technology5. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology

摘 要：Bi doped Sr TiO₃ ceramics with Sr deficiency, i.e. Sr_{1-1.5 x}Bi_xTiO₃（x=0, 0.01, 0.05, 0.1）, were prepared via conventional solid-state reaction route. A colossal permittivity（CP） over 104 with low dielectric loss less than 0.05 was obtained in x=0.05 Sr_{1-1.5 x}Bi_xTiO₃ ceramics. In addition, the dielectric constant is maintained at a value greater than 10⁴ in the range of 10²-10⁵ Hz and almost frequency independent. Phase structure analysis and density functional theory calculations suggest that the Bi_Sr^·-V"_Sr-Bi_Sr^·defect complex with hole-pinned defect-dipoles maybe responsible for the high-performance CP properties. This work gives a new way to achieve high performance CP materials in ABO₃ perovskite ceramics.

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