Determination of the Activation Energy of Defects in Ferroelectrics by the Method of Temperature Activation–Relaxation of the Dielectric Permittivity

The article proposes a method of temperature activation–relaxation of the permittivity for determining the activation energy of defects in ferroelectrics using lead zirconate–titanate Pb(Zr,Ti)O₃ samples as an example. This method is based on the analysis of relaxation of the permittivity after thermal annealing and the analysis of the temperature activation of the permittivity of the Pb(Zr,Ti)O₃ ferroelectric. The equality of the activation energy corresponding to the process of migration of oxygen vacancies and the thermal energy of the decay of the domain structure was established, which was confirmed by studying the surface of the samples by scanning electron microscopy. When this temperature was reached, the surface of the domain walls was detached from oxygen vacancies, which are pinning centers. This manifested itself in photographs of the microstructure as a change in the ordering of the domains emerging on the surface of the sample, which led to an irreversible decrease in the permittivity of the sample. For the obtained activation energies, the physical process of domain wall motion activation is established, which is determined by their pinning on structural defects (oxygen vacancies). It is assumed that the irreversible decay of the domain structure occurs when the domain walls are displaced by distances exceeding the elementary lattice parameter of the ferroelectric. The proposed method can be part of a comprehensive study that includes electrophysical, microscopic and X-ray methods.