MR value of Co/ZnO films as a function of resistivity. We fixed the composite of Co/ZnO films and varied sputtering pressures from 0.4 to 0.8 Pa; we also fixed the sputtering pressure and changed the film thickness of the ZnO layer from 0.3 to 2.5 nm. Samples A, B, and C, labeled as solid circles, are situated in the metallic, tunneling, and hopping regimes, respectively.
Quan et al. Nanoscale Research Letters 2014 9:6 doi:10.1186/1556-276X-9-6