Anotace
The project is devoted to the study of the lattice dynamics and the dielectric behaviour of ferroelectric and piezoelectric oxides with anisotropic tetragonal tungsten-bronze structure. THz, Raman and infrared spectroscopy measurements of phonons will allow us to to study the dynamics of the ferroelectric phase transitions (soft modes or central modes). Dielectric spectroscopy from 10 mHz to 20 GHz will be used for studying the relaxor ferroelectric behaviour and the contributions from domains, incommensurate modulations, and nanoregions in form of relaxations.