Domain-Wall processes and piezoelectric properties of ceramic ferroelectrics

Data of measurements of d*d, reverse static d*r and dynamical d* piezoelectric coefficients of the series of ferroelectric ceramics are analysed. It is shown that these coefficients are different for multiaxial ferroelectrics and the relation |d* d| > |d* r| is fulfilled. The obtained results are discussed on a basis of thermodynamical and statistical ideas. Various contributions to the piezoelectric coefficients of the ceramics are analysed