Effect of interface passivation on the magnetoresistanceof granular magnetite Fe 3 ( 1 − δ ) O 4

The reductive passivation of granular interface was proposed to enhance the tunneling magnetoresistance of bulk granular magnetite. For this, an annealing in paraffin wax has been applied. As a result, the low-field magnetoresistance response was increased up to 8% at 300 K and 32% at 130 K . The effect is attributed to the passivation-induced depletion of density of the tunneling-active spin-depolarized interface states. The obtained results indicate the important role of interface states in tunneling contacts with magnetite electrodes and suggest a way to control these states.