The paper proposes a new method for studying nonlinear processes in ferroelectric ceramics under external influences, based on the measurement and analysis of piezoelectric resonance spectra. The method provides high accuracy in determining complex elastic, dielectric and piezoelectric constants of piezoelectric materials, as well as their changes under external influences. To study nonlinear processes, we measured the dependences of complex electromechanical parameters of ferroelectrically «soft» piezoceramics based on PZT system on dc electric field. A physical interpretation of the results is proposed.

A new method for studying relaxation and transient processes in ferroelectric ceramics under the influence of dc electric field is proposed. Precision measurements of time dependences of complex dielectric constants of ferroelectric ceramics in the region of weak electric fields were carried out using the method of impedance spectroscopy. A comparative analysis of various methods for characterization of relaxation processes in ferroelectric ceramics is carried out. A physical interpretation of the results is proposed.