High-power resonant measurements of piezoelectric materials: Importance ofelastic nonlinearities

A resonance method for measuring the complex elastic and electromechanical properties of piezoelectric materials under high-power operational conditio ns has been developed. In this method, rectangular specimens are piezoelect rically driven into mechanical resonance. The displacement of the transvers e resonance mode is measured as a function of frequency (f) using an optica l vibrometer method in conjunction with a frequency response analyzer. Due to the wide amplitude sensitivity range of the detection system, asymmetrie s in nonlinear resonance curves with mechanical damping can be accurately m easured. The method has been applied to the study of Pb(Zr1-xTix)O-3. Under resonant high-power drive, it has been found that electromechanical nonlin earities are due to elastic ones, as the elastic and electromechanical prop erties were both found to scale with the square of the strain amplitude. Th e temperature (T) and ac electric field (E-ac) dependence of the mechanical quality factor Q(m) were also determined. Iso-Q(m) curves were constructed that can be used to predict performance criteria for high-power applicatio ns of piezoelectric materials. (C) 2001 American Institute of Physics.