Determination of the percolation threshold for (FeCoZr)x(SiO2)(100−x) Nanocomposite

Abstract

This work presents an explanation of the effect of metallic phase content x on AC electrical properties of nanocomposites (FeCoZr)x(SiO2)(100−x) and determination of the percolation threshold for series of nanocomposite samples with metallic phase content x = 48.3–82.8 at.%. Frequency and temperature dependencies of conductivity σ(f, T) and phase shift angle θ(f, T) for series of nanocomposite produced by ion-beam sputtering in pure argon atmosphere were determined. Samples with metallic phase content x < 79.8 at.% exhibit dielectric type of conductivity dσ/dT > 0. Increase in concentration of metallic phase x ≥ 79.8 at.% causes a change of conductivity character from dielectric to metallic dσ/dT < 0. Comparison of the conductivity at Tp = 20 K and conductivity at room temperature allowed to determine the percolation threshold for a series of samples of nanocomposite (FeCoZr)x(SiO2)(100−x). Metallic phase particles form the “endless cluster” that crosses though sample from the electrode to electrode in nanocomposites with x ≥ 80 at.%.