Giant magnetoresistance in nanoscale ferromagnetic heterocontacts

Abstract

A quasiclassical theory of giant magnetoresistance in nanoscale point contacts between different ferromagnetic metals is developed. The contacts were sorted by three types of mutual positions of the conduction spin-subband bottoms which are shifted one against another by the exchange interaction. A model of linear domain wall has been used to account for the finite contact length. The magnetoresistance is plotted against the size of the nanocontact. In heterocontacts the magnetoresistance effect turned out to be not only negative, as usual, but can be positive as well. Relevance of the results to existing experiments on GMR in point heterocontacts is discussed.

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: …”

“…10,16 The consideration of the system in terms of finite temperature T depends on how corresponding energy   In this section, it was assumed that voltage drop is realized only on the TC. As a first-order of the accuracy and simplicity of the npMTJ model, it was proposed that NP has a quasi-continuous energy levels, i.e., the energy level quantization due to possible quantum well states were neglected for the …”

Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

“…Previously, we developed a theory of electronic transport through a nanosized domain wall between ferromagnetic homo-and hetero-electrodes 22 in a pointlike geometry. This theory utilizes quasiclassical equations in order to describe the transport phenomena in the ferromagnetic metals, and quantum-mechanical equations for modeling the electron domain wall, which is approximated by a slope potential.…”

“…This theory utilizes quasiclassical equations in order to describe the transport phenomena in the ferromagnetic metals, and quantum-mechanical equations for modeling the electron domain wall, which is approximated by a slope potential. In this work, we apply the previously derived equation for the current 22 to the case of electronic transport through the DMTJ in a ballistic mode replacing the transmission coefficient of the domain wall potential by the tunnel transmission coefficient (which is calculated analytically for the DMTJ). The inhomogeneous terms (responsible for the pointlike geometry) were neglected due to their small contribution in the planar ballistic case.…”

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

“…An alternative theoretical approach of electronic transport through nanocontacts with and without domain walls between two FM electrodes has been developed in Ref. 20. This theory utilizes quasiclassical as well as quantum mechanical ideas and is based on extended Boltzmannlike equations.…”