Remarkable power–law temperature dependencies of inter-grain conductivity

Electrical conductivities with temperature dependencies of the type σ(T)−σ(0)∝Tp are remarkable when measurements over extended ranges of T show that p=1 or 2 over wide ranges of σ. We report on such behaviors for inter-grain conductivities of polycrystalline Sr2CrMoO6 samples. We show that for certain ranges of parameters the ‘fluctuation induced tunneling’ model fits these dependencies very well.