31. – «Graphene enhances the magnetoresistance of FeNi3 nanoparticles in hierarchical FeNi3-graphene nanocomposites»

An increase in the giant magnetoresistance of FeNi₃ nanoparticles of 20 times has been observed in FeNi₃–graphene nanocomposites synthesized using NiFe-layered double hydroxide hybrids as precursors. The magnetic, transport and magneto-transport properties of these nanocomposites are studied and compared with those of the pure FeNi₃ nanoparticles. The hierarchical structure and hybrid composition of these magnetic nanocomposites lead to the observation of two unusual magneto-transport properties, namely (i) an enhancement in the low-field magnetoresistance effects, and (ii) a crossover from negative to positive MR upon cooling down the sample.