Enhanced Piezoelectricity and Thermal Stability of Electrostrain Performance in BiFeO3-Based Lead-Free Ceramics

Hongwei Shi; Kai Li; Feng Li; Jianxing Ma; Yubing Tu; Mingsheng Long; Yilin Lu; Weiping Gong; Chunchang Wang; Lei Shan

doi:10.3390/nano13050942

Enhanced Piezoelectricity and Thermal Stability of Electrostrain Performance in BiFeO₃-Based Lead-Free Ceramics

Nanomaterials (Basel). 2023 Mar 5;13(5):942. doi: 10.3390/nano13050942.

Authors

Hongwei Shi^{1

2

3}, Kai Li⁴, Feng Li^{1

2

3}, Jianxing Ma⁵, Yubing Tu^{1

2

3}, Mingsheng Long^{1

2

3}, Yilin Lu^{1

2

3}, Weiping Gong⁴, Chunchang Wang⁵, Lei Shan^{1

2

3}

Affiliations

¹ Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui University, Hefei 230601, China.
² Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei 230601, China.
³ Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China.
⁴ Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices, Huizhou University, Huizhou 516001, China.
⁵ Laboratory of Dielectric Functional Materials, School of Materials Science & Engineering, Anhui University, Hefei 230601, China.

Abstract

BiFeO₃-based ceramics possess an advantage over large spontaneous polarization and high Curie temperature, and are thus widely explored in the field of high-temperature lead-free piezoelectrics and actuators. However, poor piezoelectricity/resistivity and thermal stability of electrostrain make them less competitive. To address this problem, (1 - x) (0.65BiFeO₃-0.35BaTiO₃)-xLa_0.5Na_0.5TiO₃ (BF-BT-xLNT) systems are designed in this work. It is found that piezoelectricity is significantly improved with LNT addition, which is contributed by the phase boundary effect of rhombohedral and pseudocubic phase coexistence. The small-signal and large-signal piezoelectric coefficient (d₃₃ and d33*) peaks at x = 0.02 with 97 pC/N and 303 pm/V, respectively. The relaxor property and resistivity are enhanced as well. This is verified by Rietveld refinement, dielectric/impedance spectroscopy and piezoelectric force microscopy (PFM) technique. Interestingly, a good thermal stability of electrostrain is obtained at x = 0.04 composition with fluctuation η = 31% (Smax'-SRTSRT×100%), in a wide temperature range of 25-180 °C, which is considered as a compromise of negative temperature dependent electrostrain for relaxors and the positive one for ferroelectric matrix. This work provides an implication for designing high-temperature piezoelectrics and stable electrostrain materials.

Keywords: BiFeO3–BaTiO3; domain structure; electrostrain; piezoelectricity; temperature stability.

Abstract

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