Quantum interference effect in strongly localized system of polymer-nanocomposites

A positive magnetoresistance (MR) is observed in the composites of magnetic nanoparticles and polymer at low temperatures. The MR decreases gradually as temperature increases and becomes negative passing through a crossover temperature regime. The MR attains minimum at 40 K and increases above this temperature. The transport and magnetotransport properties at low temperatures follow Efros-Shklovskii variable range hopping. The negative magnetoresistance has been explained by the quantum interference effect in strongly localized regime.