A Two-Band Tight-Binding Model of Spin-Polarized Transport in Magnetic Tunnel Junctions

Abstract

The main features determining spin-dependent transport in magnetic tunnel junctions are well appreciated now mainly due to ab initio calculations. Nevertheless, it seems useful to have a comparatively simple model which reproduces the salient characteristics of spin-dependent transport in magnetic multilayers. We present two-band tight-binding model of magnetic tunnel junction with the layers of arbitrary thickness and non-collinear magnetization configuration. The model accounts for different symmetry of the tunneling electrons and their mixing on the interfaces. As an illustration for double-barrier structure we calculate I-V curves and spin-transfer torque. The calculations demonstrate the resonant character of the I-V dependences. Also, the significant difference in the magnitude of the torque acting on the various planes of the same magnetic layer is found.