We study the piezoelectric resonances in poled PZT ceramics by means of a m
icroscopic model. It connects the microscopic vibrations of the ionic units
, cooperatively producing the piezoelectric effect, with the macroscopic pi
ezoelectric parameters. The behaviour at the resonance is well described in
a wide range of frequencies, allowing the calculation of piezoelectric con
stants and the electromechanical coupling factors in terms of microscopic q
uantities. (C) 1999 Elsevier Science Limited. All rights reserved.