Magnetoresistance of granular metal-oxide thin films

The magneto-transport properties of granular films consisting of ultrafine metal and metal-oxide particles containing Fe, Ni, B and O have been studied between 4 and 300 K. As a function of temperature, the films show a transition from a poorly conducting to a metallic state at 260 K. This change in the transport mechanism is also reflected in the different magnetoresistance behavior for low and high temperatures.