▎ 摘　　要

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.