The real part of AC conductance in amorphous nanocomposites ferromagnetic alloy–dielectric
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Results of AC conductivity of the granular nanocomposites consisting of amorphous ferromagnetic alloy nanoparticles (Fe0.45Co0.45Zr0.10) embedded into amorphous dielectric matrix (Al2O3) are presented and analyzed here. Conductivity measurements were made for the samples of different metal-to-dielectric ratio x (25 < x < 65 at.%) in the frequency range of 0.1–1000 kHz at temperature of 80–340 K. Real part of AC conductance at low frequencies (f ≤ 5 kHz) have shown temperature dependencies σreal(T) corresponding to Mott hopping regime at x below the percolation threshold and metallic one beyond the percolation threshold. It was shown that σreal(T) dependencies satisfactorily follow the known relations of 3D percolate models with critical indexes t ≈ 1.6, q ≈ 0.9, and s = 0.62. The numerical estimations of the density of localized states N(EF) displayed a tendency to be decreased with x increase and the electron wave-function localization length a was about 11 nm.
KeywordsPercolation Threshold Nanocomposite Film Carrier Transport Metallic Nanoparticles Critical Index
The author wishes to thank Belarusian State University especially Prof. A. Fedotov for allowing him to do this work during his devoted summer vacations for the last several years and also Prof. Yu. Kalinin from Voronezh State Technical University for presentation of the samples.
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