Epitaxial thin films of relaxor PbMg1/3Nb2/3O3 and PbSc0.5Nb0.5O3, andferroelectric PbZr0.65Ti0.35O3, Pb0.955La0.045Zr0.65Ti0.35O3, andBa0.4Sr0.6TiO3 were prepared, and their dielectric properties were studied in abroad range of the measurement conditions. In the ferroelectric state, thepresence and the change of configuration of the domains determined both thedynamic dielectric nonlinearity and the polarization hysteresis. In thin-filmrelaxors, the orientation of the randomly interacting dipoles in a random fieldwas responsible for the dynamic dielectric nonlinearity, while the observedhysteresis was suggested to arise due to connection between the applied fieldand the relaxation times of both the dipoles and the internal field. Inthin-film (Ba,Sr)TiO3, the high-temperature dielectric hysteresis was found tobe relaxorlike.
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