Decoding intrinsic and extrinsic contributions for high piezoelectricity of CBT-based piezoelectric ceramics

Abstract

The excellent electrical properties of CaBi₄Ti₄O₁₅-based piezoelectric ceramics come from both intrinsic and extrinsic contributions. Nb⁵⁺/Mg²⁺ co-doping into the Ca_0.6(Na_0.5Bi_0.5)_0.4Bi₄Ti₄O₁₅ ceramic results in increased oxygen octahedron tilt degrees and stretches along the direction of spontaneous polarization (P_s), increasing the intrinsic contribution. Increased grain size is more conducive to local domain switching, which is beneficial to the extrinsic contribution. Effectively enhanced electrical properties are obtained in the Ca_0.6(Na_0.5Bi_0.5)_0.4Bi₄Ti_3.925(Nb_2/3Mg_1/3)_0.075O₁₅ ceramic: a piezoelectric coefficient of d₃₃ = 25.5 pC N⁻¹ (20 °C), a remnant polarization of P_r = 11.2 μC cm⁻², and a coercive field of E_c = 69.2 kV cm⁻¹. Moreover, high temperature stability (d₃₃ = 23.9 pC/N at 600 °C) and resistivity (ρ = 1.0 × 10⁶ Ω cm at 600 °C) are obtained. This work can promote the development of high-temperature piezoelectric devices.