The character of low-infralow-frequency di- electric spectra of ferroelectrics and related materials, their transformation with temperature, electric field and aging time, the temperature dependencies of relaxation times at phase and structural transitions are evidence of their fractality. The analysis of optical microscope re- search brought to light the fractal features of domain boundaries and their temporal evolution. The kinetic equations modified by introducing of the fractional de- rivatives, percolation and fractal models describe the pre- ponderance of the dielectric spectra and explain the criti- cal slowdown of relaxation. The fractal dimensionalities evaluated by experiments and their change at phase tran- sitions have being discussed in comparison with the per- colation models and the dynamic scaling theory.
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