Fabrication of magnetic tunnel junctions with a metastable bcc Co ₃ Mn disordered alloy as a bottom electrode

Abstract

Abstract We fabricated MgO barrier magnetic tunnel junctions (MTJs) with a Co 3 Mn alloy bottom and FeCoB top electrodes. The (001)-oriented epitaxial films of the metastable bcc Co 3 Mn disordered alloys obtained showed saturation magnetization of approximately 1640 emu cm −3 . The transmission electron microscopy showed that the MgO barrier was epitaxially grown on the Co 3 Mn electrode. Tunnel magnetoresistance of approximately 150% was observed at room temperature after the annealing of MTJs at 350 °C, indicating that bcc Co 3 Mn alloys have relatively high spin polarization.