Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

Abstract

We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

Tunnel Magnetoresistance and Temperature Related Effects in Magnetic Tunnel Junctions with Embedded Nanoparticles

“…1(b) and Fig. 1(c 10 The first term has a simple form (1) and represents simple approach which can be used also for description of the direct electron tunneling in MTJs [5][6][7][8][9] In case of symmetric nonmagnetic a -spot contact 2) were simplified in the limit of the nonmagnetic symmetric a-spot contact: …”

“…The key parameter is a wave-vector value NP k in NP. The double barrier approach 5,6 was integrated into a-spot model of the magnetic point-like contact.…”

Semiclassical Green’s functions of magnetic point contacts

“…To conclude this section, we note that obtained expression (40) for the antisymmetric Green's function permits numerically calculating the spin-dependent conductivity and the magnetoresistance in the following structures: at the magnetic planar contacts when only the transmission coefficient D α is used (see, e.g., [12]), at the magnetic point heterocontacts when the two terms D α and F heter α (k) are taken into account (see [7]), and at the magnetic point heterocontacts when the more general case l ∼ a is studied with the term F grad α (k) taken into account (see [13]). This work is supported by the Russian Foundation for Basic Research (Grant No.…”

Impact of lattice strain on the tunnel magnetoresistance in Fe/insulator/Fe and Fe/insulator/La0.67Sr0.33MnOUseinov1, Saeed2, Singh3 et al. 2013Phys. Rev. B7080View full textAdd to dashboardCite

“…Boundary conditions on the interfaces of the junction are taken into account as a key part of the solution. The theory can be adapted to the case of ballistic transport through single-barrier 14 and double-barrier 21 planar junctions. Using the universality of the above technique, we formulate a multichannel (or multiband) approach following the ideas of Ref.…”