• Okal, Paweł
• Gałaszkiewicz, Piotr
• Pogorielov, Maksym
• Koltunowicz, Tomasz Norbert
• Ruban, Anatolyi
• Kupchishin, Anatolyi
• Bondariev, Vitali
• Zukowski, Pawel
• Pogrebnjak, Alexander

Abstract

<jats:p>In this paper, the frequency-temperature dependence of the conductivity and dielectric permittivity of nc-TixZr1−xC+α-Cy (0.0 ≤ x ≤ 1.0) nanocomposites produced by dual-source magnetron sputtering was determined. The films produced are biphasic layers with an excess of amorphous carbon relative to the stoichiometric composition of TixZr1−xC. The matrix was amorphous carbon, and the dispersed phase was carbide nanoparticles. AC measurements were performed in the frequency range of 50 Hz–5 MHz at temperatures from 20 K to 373 K. It was found that both conductivity and permittivity relationships are determined by three tunneling mechanisms, differing in relaxation times. The maxima in the low- and high-frequency regions decrease with increasing temperature. The maximum in the mid-frequency region increases with increasing temperature. The low-frequency maximum is due to electron tunneling between the carbon films on the surface of the carbide nanoshells. The mid-frequency maximum is due to electron transitions between the nano size grains. The high-frequency maximum is associated with tunneling between the nano-grains and the carbon shells. It has been established that dipole relaxation occurs in the nanocomposites according to the Cole-Cole mechanism. The increase in static dielectric permittivity with increasing measurement temperature is indicative of a step polarisation mechanism. In the frequency region above 1 MHz, anomalous dispersion—an increase in permittivity with increasing frequency—was observed for all nanocomposite contents.</jats:p>

Topics

• nanoparticle
• nanocomposite
• impedance spectroscopy
• dispersion
• surface
• amorphous
• Carbon
• grain
• phase
• carbide