Electrical resistivity of copper-silica nanocomposites synthesized by electrodeposition

Composites containing copper particles with nanometer dimensions in a silica gel medium have been synthesized by an electrodeposition technique. The precursor composition of the gel was in the system Cu(NO3)2-SiO2 and the copper particle diameters were in the range of 3.2-11.4 nm. The dc electrical resistivity of pellets obtained from the nanocomposite powders was measured in the temperature range of 110-300 K. A temperature dependence with a fractional exponent of 0.25 was observed. This behavior has been explained on the basis of a variable range hopping mechanism