Sequential and coherent electron tunneling in ferromagnetic planar junctions

We consider electron tunneling in ferromagnetic single-barrier and double-barrier planar junctions. The single-barrier junctions include additional thin films at the electrode/barrier interfaces. In the case of double-barrier systems, electron tunneling is considered in both sequential and coherent tunneling regimes. Generally, all components of the junctions, including external and central electrodes, thin metallic films and barriers can be ferromagnetic. We present numerical results for the following junctions: (i) single-barrier junctions with nonmagnetic barrier and nonmagnetic electrodes, but with thin ferromagnetic metallic films on both sides of the barrier; (ii) double-barrier junctions with ferromagnetic external electrodes and nonmagnetic barriers and central electrode; (iii) double-barrier junctions with ferromagnetic barriers and nonmagnetic central and external electrodes. (C) 2001 Elsevier Science B.V. All rights reserved.