Magneto-Resistance Effect in γ'-Fe₄N/CrO₂ Granular System

Abstract

  Magnetization and magneto-resistance ratio (MRR) were measured for (γ'-Fe₄N)_x(CrO₂)_1-x granular system between 77 K and 300 K, where x is the mole ratio of Fe₄N in the measured samples. The γ'-Fe₄N and CrO₂ are the ferromagnetic half metals with high Curie temperature and relatively high electrical conductivity. Since the spin polarization coefficient P of conduction electrons is nearly −1 in Fe₄N and 1 in CrO₂, the various junctions in this system are expected to show the competing tunneling magnetoresistance (TMR) effects. The MRR of this system showed the compensated behavior at x around 0.2, which is the percolation threshold of connectivity of Fe₄N grains.