Oscillatory Tunneling Magnetoresistance in Fe3O4/n-GaAs/Fe3O4 Junction

Oscillatory tunneling magnetoresistance (TMR) as a function of the length of the n-GaAs channel is investigated theoretically for an Fe₃O₄/n-GaAs/Fe₃O₄ junction with a Schottky barrier between half metallic Fe₃O₄ and the n-GaAs semiconductor. In the n-GaAs channel, a tunneling current with ballistic and diffusive components is taken into account. The ballistic component results in oscillations of the MR with a single period, while the diffusive one leads to their decay with the thickness of the GaAs channel. Compared with the conventional FM/I/NM/I/FM double tunneling junctions where FM is a ferromagnet, NM, a normal metal, and I, an insulating barrier, the TMR is much larger and the spin-dependent current transmits farther.