Performance of Fe3O4/AlOx/CoFe magnetic tunnel junctions based on half-metallic Fe3O4 electrodes

Magnetic tunnel junctions (MTJs) with Fe3O4 electrodes were prepared to observe spin- dependent tunneling effect of half-metallic materials through an insulating AlOx barrier at room temperature (RT). In addition, the plasma treatment with Ar gas was in situ performed to improve surface morphology of an as-deposited Fe3O4 electrode. After Ar plasma treatment, the root mean square of as-deposited Fe3O4 thin film was decreased from 4.5 Å to 2.5 Å. Magnetoresistance (MR) and electrical breakdown voltage of the MTJ were found to be 11% and 0.8 V at RT, respectively. This large MR value is ascribed to the enhanced surface morphology of Fe3O4 electrode after plasma treatment. This MR value at RT gives a potential way of using Fe3O4 thin films in the spintronic devices, together with the enhanced surface treatment technique.