Bias Voltage Controlled Positive Magnetoresistance of Fe_0.05-C_0.95/Si Heterostructures

Fe-doped amorphous carbon films of about 100nm in thickness are deposited on n-type silicon substrates by pulsed laser deposition (PLD), and positive magnetoresistance (MR) is observed for these Fe-doped amorphous carbon/n-Si heterostructures under current-perpendicular-to-plane configuration at forward bias. Two MR peaks are observed in the temperature range 40-120K and the positive MR varies with applied bias voltage. This bias voltage controlled MR may be related to the magnetic-field-controlled freeze out effect and recombination through the deep trapping states in the Fe-doped carbon films.