Resistance and magnetoresistance of annealed amorphous carbon films containing Fe3C nanograins

The temperature-dependent resistance and the field-dependent magnetoresistance were measured for films annealed at temperatures from 250 deg. C to 550 deg. C for a period of 60 min. Results of temperature-dependent resistance show electrical tunneling conductance in the films annealed at Ta=250 deg. C and 350 deg. C only. The largest magnetoresistance ratio (MR) of 23% at temperature T=2 K was observed for Ta=350 deg. C. The variations of both the temperature dependence of resistance and the magnetoresistance with the annealing temperature are discussed