Fractal nature of large-scale inhomogeneous structure in ferroelectrics with a diffuse phase transition

Abstract

The peculiarities of the electric fieldinduced phase transition in lead magnoniobate crystals (PMN), and the nature of the spatially non-uniform structure arising at this transition in PMN and also at the first-order phase transition in lead scandotantalate (PST) crystals have been investigated by means of the small-angle light scattering (SALS) technique. The experimental results confirm for the first time a percolation-type phase transition in the PMN crystal upon heating in an electric field. The physical nature of the large-scale inhomogeneous structure appearing at the phase transition is discussed in terms of a fractal model.