Electrical properties of nanostructures (CoFeZr)x + (Al2O3)1−x with use of alternating current

The observed variations of real part AC electrical conductivity with temperature and frequency σreal(T, f) in the as-deposited films display transition from dielectric to metallic behaviour when crossing the percolation threshold xC in the studied nanocomposites. After annealing of the samples below the xC the σreal(T, f) progress follows the hopping law of electron conductivity with sigmoidal frequency dependence. The samples being far beyond the percolation threshold revealed transition from metallic to activational σreal(T) law after high-temperature annealing attributed to the internal oxidation of metallic nanoparticle by excess of oxygen presented in the as-deposited samples.