| Autor: |
Paweł Żukowski, Piotr Gałaszkiewicz, Vitali Bondariev, Paweł Okal, Alexander Pogrebnjak, Anatolyi Kupchishin, Anatolyi Ruban, Maksym Pogorielov, Tomasz N. Kołtunowicz |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
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| Zdroj: |
Materials, Vol 15, Iss 22, p 7908 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
1996-1944 |
| DOI: |
10.3390/ma15227908 |
| Popis: |
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. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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