Nonlinear shear response in (K,Na)NbO3-based lead-free piezoelectric ceramics

The piezoelectric shear response of 94.0(Ka0.5, Na0.5)NbO3 (KNN) + 5.0LiNbO3 (LN) + 0.5SrTiO3 (ST) + 0.5BiFeO3 (BF) ceramics was investigated by Laser Doppler Vibrometry (LDV) and resonance-antiresonance method. From resonance-antiresonance method, the piezoelectric d15 constant was obtained to be 273 pC/N. The shear strain obtained by LDV at the frequency of 150kHz showed strong nonlinearity. This suggested that the domain contribution to piezoelectric response in shear mode of KNN-LN-ST-BF ceramics existed at the operational frequency for the shear mode divices.