Magnetization and Giant Negative Magneto-Resistance in Nano-Scale Ni3-δMn1+δ in Pulsed Magnetic Fields up to 25 T

Abstract

Magneto-transport phenomena of slightly Mn-rich sample in the host Ni3-Mn system were investigated on giant-negative magneto-resistance of 15% in pulsed high magnetic fields up to 25 T. We prepared nano-scale crystals of Nin (0≤≤0.05) fabricated by rapid quenching method with a mono-role and by optimum annealing to obtain the maximum magneto-resistance effect in the longitudinal configuration of sample currents and magnetic fields. The negative magneto-resistance observed in this study was interpreted as the scattering decrease of conduction electrons by anti-parallel spin pairs composed of Mn-Mn deviated from the stoichiometry. This physical mechanism also reflects the coherent length change of itinerant electrons, caused by the scattering by the comparable short-range spin disorder of Mn-Mn pairs in the nano-scale crystal grain.