Fractality and dielectric spectra of ferroic materials

Abstract

The character of low-infralow-frequency dielectric 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 research brought to light the fractal features of domain boundaries and their temporal evolution. The kinetic equations modified by introducing of the fractional derivatives, percolation and fractal models describe the preponderance of the dielectric spectra and explain the critical slowdown of relaxation. The fractal dimensionalities evaluated by experiments and their change at phase transitions have being discussed in comparison with the percolation models and the dynamic scaling theory.

Key words:

• Ferroelectrics
• Dielectric spectroscopy
• Irreversible thermodynamics
• Critical phenomena
• Domains
• Fractals
• Fractal dimensionalities