Positive linear magnetoresistance in Fex–C1−x composites

Abstract A large positive magnetoresistance (MR) has been found in micro-sized Fe x –C 1− x composites. At a magnetic field of 5 T, the Fe 0.2 –C 0.8 composite has the largest MR, 53.8% and 190% at room temperature and at 5 K, respectively. The magnetic field dependence of the MR can be described approximately as MR∝ B n , and the value of exponent n is determined by the Fe weight concentration and temperature, ranging from 1/4 to 6/4. It appears that Fe x –C 1− x has a linear field dependence of the positive MR at different temperatures. The possible mechanism for the positive MR is discussed.