Electro-elastic features of α-BiB3O6 crystals with a monoclinic symmetry

Abstract

The monoclinic α-BiB₃O₆ (BIBO) crystal is an important piezoelectric material for high-temperature sensing applications. As a prerequisite to the design of piezoelectric sensors, the electro-elastic features of the BIBO crystal should be determined. Herein, the full set of electro-elastic coefficients was obtained using the impedance method, modified quasi-static measurements, and the laser interferometry method. The independent piezoelectric coefficients were determined to be d₁₄ = 10.9, d₁₆ = 16.4, d₂₁ = −15.6, d₂₂ = 40.0, d₂₃ = 2.5, d₂₅ = −9.8, d₃₄ = 20.6, and d₃₆ = 6.2 pC N⁻¹ at room temperature. Moreover, the optimum crystal cuts were discussed based on the piezoelectric coefficient matrix, where the highest longitudinal piezoelectric coefficient was for the Y-oriented crystal cut; the highest transverse length extensional piezoelectric coefficient was for the YXt/−15° crystal cut, and the maximum thickness shear piezoelectric coefficient was for the XYw/50.6° and XYw/−50.6° crystal cuts. Furthermore, the maximum face shear piezoelectric crystal cut with was achieved for the Y/−60° and Y/30° crystal cuts, which were expected to excite SH₀ waves for nondestructive testing and structural-health inspection.