Conduction mechanism in granular Ru02-based thick-film resistors

Abstract

The conductivity of a commercial thick-film resistor is measured between 4 K and 15 mK and in magnetic fields up to 7 Tesla. The data can be described by the variable-range hopping mechanism with a Coulomb gap in the density of states. The negative magnetoresistance may be attributed to quantum-interference effects in the strongly localized regime.