Resonant tunnel magnetoresistance in double-barrier magnetic tunnel junctions: A non-equilibrium Green's function study

The non-equilibrium Green's function technique is used to study the transport characteristics of double-barrier magnetic tunnel junctions. The exchange coupling strength of the electrodes is found to be crucial in deciding the magnetoresistance characteristics of these devices. At sufficiently large values of the magnetic coupling strength, the device is found to exhibit resonant tunnel magnetoresistance and its magnitude is found to be large. The existence of pure spin currents in these devices when there is antiferromagnetic coupling between the end electrodes is found to be the primary cause of resonant tunnel magnetoresistance. The influence of the band occupation of the electrodes and the many-body interaction present in the electrode regions on the spin current and magnetoresistance are also studied. Copyright (C) EPLA, 2013