Hoping conductance in nanocomposites (FeCoZr)x(SiO2)(100-x) produced in mixed Ar and O2 atmosphere

The work presents the results of determination of chemical composition of nanocomposites (FeCoZr)x(SiO2)(100-x) produced by ion-beam sputtering in mixed argon-oxygen atmosphere. Atomic percentage of elements of metallic and dielectric phases was obtained for series of composite samples with different metallic phase content x by using of scanning electron microscopy (SEM) with attachment for X-ray microanalysis. Analysis of SEM results showed that ratio of elements forming composition on dielectric phase nf is less then be expected.
Electrical properties of nanocomposite (FeCoZr)x(SiO2)(100-x) were investigated based on measurement of frequency-temperature dependencies of conductivity σ(f,T) and frequency factor α(f,T). The conductivity is almost constant throughout the entire frequency range but increases with increasing temperature for samples with lower metallic phase content x ≤ 55,05 at.%. For samples with x ≥ 61,58 at.% the conductivity have constant values in low-frequency area, then there is an increase in conductivity with further stabilization at higher frequencies. The increase of conductivity on σ(f) corresponds to reaching the maximum values of frequency factor α on the frequency dependencies α(f). The increase in σ along with the increase in frequency indicates an hopping mechanism of conduction of charges in the nanocomposite.