Scaled frequency-dependent transport in the mesoscopically phase-separated colossal magnetoresistive manganite La0.625-yPryCa0.375MnO3

We address the issue of massive phase separation (PS) in the manganite family of doped Mott insulators through ac conductivity measurements on La0.625-yPryCa0.375MnO3 (0.375 <= y <= 0.275), and establish the applicability of the scaling theory of percolation in the critical regime of the PS. Measurements of dc resistivity, magnetization [M(T)], and electron diffraction show incomplete growth of a ferromagnetic (FM) metallic component on cooling the high temperature charge-ordered (CO) phase well below the CO temperature. The impedance parallel to Z(T,f)parallel to measured over a frequency (f) range of 10 Hz-10 MHz in the critical regime follows a universal scaling of the form approximate to R(T,0)g(f xi(2+theta)), with theta approximate to 0.86 and the normalized correlation length varying from 1 to 4, suggesting anomalous diffusion of holes in percolating FM clusters.