Observation of enhanced positive magnetoresistance at low temperatures in Ni0.8Fe0.2/C granular composites

(Ni0.8Fe0.2)xC100−x (x = 0-50%) granular compositions were prepared using mechanically alloyed nanocrystalline NiFe powders and graphite. Magnetic measurements and structural data on mechanically alloyed samples show the presence of dominant NiFe phase along with fcc-Ni phase. All the samples exhibit positive magnetoresistance (MR) in the whole temperature range and applied field range of present study. The analysis of the magnetization and MR data suggests that large positive MR could be due to the graphite matrix rather than magnetic particle contribution.