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High temperature dielectric, ferroelectric and piezoelectric properties of Mn-modified BiFeO3-BaTiO3 lead-free ceramics

Li, Qiang, Wei, Jianxin, Cheng, Jinrong, Chen, Jianguo
Journal of materials science 2017 v.52 no.1 pp. 229-237
ceramics, electrical properties, manganese, temperature
Lead-free and high-temperature 0.71BiFeO₃-0.29BaTiO₃ ceramics with Mn modification (BF-BT-x %Mn) were fabricated by conventional solid-state reaction method, and the high temperature dielectric, ferroelectric and piezoelectric properties were investigated. All compositions exhibited pseudo-cubic phases. Mn modification improved the electrical properties of BF-BT solid solutions at both room and high temperature. The Curie temperature T C, depolarization temperature T d, dielectric constant ε ᵣ, dielectric loss tanδ, piezoelectric constant d ₃₃, electromechanical coupling factor k ₚ, remnant polarization P ᵣ of BF-BT-1.2 %Mn ceramics were 506, 500 °C, 556, 0.04, 169 pC N⁻¹, 0.373, 31.4 μC cm⁻², respectively. The ε ᵣ, tanδ, and k ₚ of BF-BT-1.2 %Mn ceramics were stable with the increase of temperature until 500 °C. The coercive field E c of BF-BT-1.2 %Mn ceramics was nearly 30 kV cm⁻¹ at 200 °C, which was much larger than those of PZT, BS-PT,BNT and KNN ceramics. The high field strain coefficient d*₃₃ reached as large as 525 pm V⁻¹ at 200 °C. These results showed that the BF-BT-x %Mn ceramics were promising candidate for high temperature piezoelectric applications.