ISSN 1064-2269, Journal of Communications Technology and Electronics, 2011, Vol. 56, No. 2, pp. 142–144. © Pleiades Publishing, Inc., 2011. Original Russian Text © U. Abdurakhmanov, F.T. Boimuratov, G.I. Mukhamedov, A.S. Fionov, G.Yu. Yurkov, 2011, published in Radiotekhnika i Elektronika, 2011, Vol. 56, No. 2, pp. 160–162. 142 INTRODUCTION Previously, we synthesized composites based on a phenylone matrix containing nickel micro- and nano- particles and investigated the electric conductivity of these composites near the percolation threshold [1]. It was established that near the percolation threshold, the experimental dependence of the electric conductivity on the fractional content of nickel nanoparticles differs from the dependence calculated using the percolation theory. This disagreement was considered within a spatial struc- tural hierarchical model that suggests the formation of a continuous spatial structure from tunnel-coupled con- ductors [2]. In this study, we present data on the permit- tivity of composites based on the phenylone matrix with nickel-bearing particles near the percolation thresholds calculated in [1] for composites with nickel micro- and nanoparticles. 1. EXPERIMENT Composites of two types were prepared on the basis of the phenylone matrix: the first one with nanodimen- sional nickel particles and the second one with nickel microparticles. A technique of fabrication of such com- posites and data on their structure were reported in detail in [1]. To perform permittivity measurements, 2-mm- thick tablets 15 mm in diameter were prepared by hot pressing the initial powder samples. A block diagram of the facility for measuring the capacitance of the samples is shown in Fig. 1. the capacitance of the samples placed into a plane capacitor was measured within the frequency range f = 20-10 3 Hz. Using the results obtained, the frequency dependence of the permittivity was plotted. The permit- tivity values at the measuring frequency were calculated by the formula (1) 0 , Ch S ω ω ε = ε where ε ω and С ω are the permittivity and capacitance of a sample at a specified frequency, respectively; h is the thickness of a sample; S is the surface area of the electrodes deposited onto the planar sample surfaces; and ε 0 is the electric constant. Static permittivity ε was obtained by extrapolation of the frequency depen- dences of ε at f = 20–200 Hz to the zero frequency (Fig. 2). The error of determination of the static per- mittivity was 2%. 2. DISCUSSION OF THE RESULTS The analysis of permittivity ε of composites based on phenylone and nickel nanoparticles at different concen- trations of the filler shows that the entire frequency range 20–10 3 Hz can be divided in two sections with different permittivity behaviors. In the frequency range 20– 200 Hz, ε of the composites substantially decreases with increasing frequency. During further frequency growth (200–10 3 Hz), ε changes insignificantly. The decrease in the permittivity of the composites with increasing fre- quency can be explained by the Maxwell–Wagner effect for inhomogeneous dielectrics [3], i. e., accumulation of the charge on the polymer-conducting filler interface The Permittivity of Phenylone-Based Composites with Nickel Particles U. Abdurakhmanov, F. T. Boimuratov, G. I. Mukhamedov, A. S. Fionov, and G. Yu. Yurkov Received January 26, 2010 Abstract—Composites consisting of a phenylone matrix and nickel-bearing particles are fabricated. The per- mittivity of composites with nickel particles near the percolation threshold is studied. The experimental dependence of the permittivity on the bulk content of nickel nanoparticles in a composite below this thresh- old is found to be different from that calculated using the percolation theory. DOI: 10.1134/S1064226911010013 ELECTRODYNAMICS AND WAVE PROPAGATION 1 2 3 C x Fig. 1. Block diagram of the facility for measuring the capac- itance of samples: sinusoidal signal generator G3-33 (1), capacitor bridge E8-2 (2), and null detector F510 (3).