Temperature Dependence of Conduction and Magnetoresistance Properties in Co-TiO2 Non-Uniform Nanocomposite Films

This is the authors' abstract. We don't add key points for this paper.

nanocomposite films are prepared via magnetron sputtering. With substrate temperature increasing, the particles undergo agglomeration, and this non-uniform structure transits from the superparamagnetic-particle Co distribution to the particle-cluster Co distribution. Consequently, the MR decreases from 6% to 1%, owing to low resistivity. To investigate the electronic transport mechanism, the microstructural analysis and temperature-dependent fitting calculations of conduction and MR were investigated. In this study, non-uniform nanocomposite films with a broad particle size distribution were fabricated. With testing temperature decreasing, electron transport changes from higher order hopping to higher order cotunneling processes. The non-uniform films deposited at room temperature exhibited a negative MR up to 30% at 2 K, which was attributed to higher order cotunneling in the Coulomb blockade regime and explained by establishing a non-uniform multi-channel conduction model.