Oscillatory Tunneling Magnetoresistance in Fe<sub>3</sub>O<sub>4</sub>/n-GaAs/Fe<sub>3</sub>O<sub>4</sub> Junction

Abstract

Spintronics strives to revolutionize conventional electronics by integrating magnetic materials with semiconductor devices, such as the spin field effect transistor (SFET)[1], which not only improve the capabilities of electronic devices, but develop new functionalities. For electrodes of spin injection and detection in SFET device, half metallic Fe 3 O 4 is an attractive candidate because its high Curie temperature of 858 K, large spin polarization near 100% at the Fermi level and relatively high electronic conductivity at room temperature, which is believed to benefit the injection of spin carriers into the semiconductors.[2] For ferromagnetic metal(FM)/ Semiconductor system, Fe 3 O 4 / GaAs is a very promising system for the fabrication of magnetoelectronic devices due to the Schottky contact of the Fe 3 O 4 /GaAs interface[3,4], which is crucial for studying the behaviors of spin dependent transportation for the devices. It is reported that in a FM/I/NM/I/FM double tunnel junction, where NM is the normal metal, and I the insulating barrier, theories predicted an oscillation of the tunneling magnetoresistance (TMR) effect as a function of the NM layer thickness because the spin polarization of the tunneling electron oscillates as a result of the resonant tunneling. Furthermore, Quantum oscillation of spin polarization in GaAs channel was experimentally demonstrated. In this paper, we have presented a theoretical approach to the tunneling conductance and TMR in a Fe 3 O 4 /GaAs/Fe 3 O 4 magnetic double tunnel junction with both ballistic and diffusive components.