Open AccessВлияние углерода на электрические свойства объемных композитов на основе окиси меди
Author(s) -
Ю Е Калинин,
М.А. Каширин,
В. А. Макагонов,
С.Ю. Панков,
А. В. Ситников
Publication year - 2018
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2018.04.45674.272
Subject(s) - materials science , seebeck coefficient , electrical resistivity and conductivity , variable range hopping , nanocrystalline material , percolation (cognitive psychology) , composite material , percolation theory , percolation threshold , condensed matter physics , ceramic , conductivity , thermal conduction , thermal conductivity , nanotechnology , chemistry , electrical engineering , physics , neuroscience , engineering , biology
The effect of carbon filler on the electrical resistance and the thermopower of copper oxide-based composites produced by ceramic technology by hot pressing has been studied. It is found that the dependences of the electrical resistivity on the filler concentration are characteristic by S-like curves that are typical of percolation systems; in this case, the resistivity decreases more substantially as the carbon content increases as compared to the decrease in thermopower value, which is accompanied by the existence of the maximum of the factor of thermoelectric power near the percolation threshold. The studies of the temperature dependences of the resistivity and the thermopower at low temperatures show that, in the range 240–300 K, the predominant mechanism of the electrotransfer of all the composites under study is the hopping mechanism. At temperatures lower than 240 K, the composites with a nanocrystalline CuO matrix have a hopping conductivity with a variable hopping distance over localized states of the matrix near the Fermi level, which is related to the conductivity over intergrain CuO boundaries. A schematic model of the band structure of nanocrystalline CuO with carbon filler is proposed on the base of the analysis of the found experimental regularities of the electrotransfer.