In-situ acoustical monitoring of the effective-polarization hysteresis in cellular polypropylene ferroelectrets

The build-up of the effective polarization in ferroelectrets under suitable charging voltage waveforms was studied by means of acoustical measurements and dielectric resonance spectroscopy. A polarization-voltage (P-V) hysteresis loop was obtained by analyzing the data in the light of an existing model for the piezoelectric d
₃₃
coefficient of ferroelectrets.