Features of the dynamic pyroelectric response and the local domain structure in PZN-PT crystals

In this work, the polarization distribution over the volume of (1-x)Pb(Zn_1/3Nb_2/3)O_3-xPbTiO₃ crystals of the directions [001] and [111] was studied by the method of dynamic pyroelectric response. It is established that the value of the pyroelectric coefficient in the samples of both directions is the same. The domain structure of the studied crystals was visualized by piezoresponse force microscopy. It is shown that on the surface of the initial single crystals of these directions there is a small-sized labyrinth-like domain structure from 50 to 500 nm, characteristic of ferroelectric relaxors. At a depth of 50 microns from the crystal surface, a larger domain structure with a characteristic micron-scale domain size is observed. To determine the average thickness of a layer with an inhomogeneous polarization distribution, a theoretical model was used that analytically describes the possibilities of a dynamic pyroelectric method for studying the near-surface layer of ferroelectric materials. Theoretical calculations have shown that this method allows us to obtain accurate data on the thickness of the layer and its polarization state. It has been experimentally established that in a single crystal 0,955Pb(Zn_1/3Nb_2/3)O₃-0,045PbTiO₃ of the direction [001], the secondary pyroelectric effect contributes to the overall pyroelectric response much more than for the direction [111] due to the large value of the piezoelectric coefficient.

relaxors, pyroelectric effect, polarization, piezoelectric force microscopy, domain structure