Hopping Conductance in Nanocomposites $(Fe_{0.45}Co_{0.45}Zr_{0.10})_{x}(Al_2O_3)_{1 - x}$ Manufactured by Ion-Beam Sputtering of Complex Target in $Ar+O_2$ Ambient Gas

We report the investigation of a real part of the admittance σ of granular nanocomposites $(Fe_{0.45}Co_{0.45}Zr_{0.10})_{x}(Al_2O_3)_{1 - x}$ with 0.30 < x < 0.70 in the dielectric (hopping) regime. An analysis of the σ(T, f, x) dependences in the as-deposited and annealed films over the temperature 77 K < T < 300 K and frequency 50 < f < $10^6$ Hz ranges displayed the predominance of an activation (hopping) conductance mechanism with dσ/ dT > 0 for the samples below the percolation threshold $x_{C}$ ≈ 0.76 ± 0.05. Based on the earlier models for hopping AC conductance, computer simulation of the frequency coefficient $α_{f}$ of hopping conductance depending on the probability of jump p, frequency f, and also on the shape of σ(f) curve was performed. The experimental and simulation results revealed a good agreement.