Some specificities of the pyro- and piezoelectric phenomena in heterogeneous ferroelectric materials

A system of equations has been constructed in order to find effective pyroelectric, dielectric, piezoelectric, elastic and thermoelastic constants of heterogeneous materials using the method of self-consistency. By means of these equations the characteristics are simulated of the electrically depoled piezoceramics and of composites with antiparallel polarization of the components. Such a composite, being a mixture of BaTiO 3 and PZT-19 ceramic particles, manifests at a certain concentration of PZT-19 high pyroelectric properties but does not practically possess the piezoeffect. But at another concentration it is a strong piezoelectric without any pyroeffect.