Influence of media surrounding piezoelectric ceramics on current-jump phenomena

The relationship between the viscosity of media and the current-jump phenomenon, which appears in piezoelectric ceramics driven at high power levels, was studied. With increasing viscosity of the medium, the magnitude of the current drop of the jump phenomenon became smaller, and the driving voltage required for the current jump increased. In order to elucidate the origin of the viscosity effects, we focused on the apparent resonance resistance that increased under medium viscosity conditions. The influence of apparent resonance resistance was theoretically discussed using the equation introduced from the nonlinear piezoelectric equation. The theoretical values agree well with the measured ones. The current-jump phenomenon hardly appears in high-viscosity media because apparent resonance resistance of the sample increases with increasing viscosity of the media.