1. Phase transition, ferroelectric and piezoelectric properties of B-site complex cations (Fe0.5Nb0.5)4+-modified Ba0.70Ca0.30TiO3 ceramics.
- Author
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Li, Cai-Xia, Hong, Yue-Nan, Yang, Bin, Zhang, Shan-Tao, Liu, Dan-Qing, Wang, Xi-Ming, Liu, Qian, Zhao, Lei, and Cao, Wen-Wu
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LEAD-free ceramics , *PIEZOELECTRIC ceramics , *GRAIN size , *PHASE transitions , *DIELECTRIC loss , *CERAMICS , *ELECTRIC properties , *TRANSITION temperature - Abstract
Ba 0.70 Ca 0.30 Ti 1- x (Nb 0.5 Fe 0.5) x O 3 lead-free ceramics (abbreviated as BCTNF x , x = 0–0.12) were prepared by solid-state reaction method. The influence of B-site (Fe 0.5 Nb 0.5)4+ substitution on phase structure, microstructure, dielectric, ferroelectric and piezoelectric properties of Ba 0.70 Ca 0.30 TiO 3 ceramics were systematically studied. The BCTNF x ceramics consist of diphasic tetragonal (T) and orthorhombic (O) phases at x = 0–0.04, pseudocubic (PC) and O phases at x = 0.05–0.08, cubic (C) and O phases at 0.08 < x ≤ 0.12. Increase of (Fe 0.5 Nb 0.5)4+ doping improves sinterability, depresses the ferroelectric - paraelectric phase transition temperature (T m) monotonically from 128 °C at x = 0 to -86 °C at x = 0.12, induces enhanced relaxor behavior and weakens piezoelectric properties. The room temperature relative dielectric constant (ε r) and dielectric loss tangent (tan δ) increase with increasing x and reach the maximum values of 4869 and 0.06 respectively at x = 0.06. Whereas the average grain size (abbreviated as AGS), ferroelectric properties and electric field induced strain increase significantly by introducing 2.0 mol% B-site complex cations (Fe 0.5 Nb 0.5)4+ into Ba 0.70 Ca 0.30 TiO 3 ceramics. The BCTNF0.02 ceramics achieve optimal electrical properties with ε r = 1268, tan δ = 0.03, T m = 102 °C, P max = 12.8 μC/cm2, P r = 6.1 μC/cm2, E C = 6.0 kV/cm, d 33 = 117 pC/N, k p % = 0.18%, Q m = 236, bipolar S max % = 0.20%, unipolar S max % = 0.16% and d 33 ∗ = 314 pm/V. The variation of electrical properties of BCTNF x ceramics is attributed to the combined action of grain size effect, phase transition, weakness of octahedral distortion, clamping effects of the internal bias electric field E i on domain wall motion induced by B-site cations (Fe 0.5 Nb 0.5)4+ displacement. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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