Quantum-well resonance is achieved through partial confinement in magnetic tunnel junctions (MTJs), which provides an additional operable degree of freedom to regulate quantum-well levels. Using Al/Fe/MgO/Fe/Al and Ag/Al/Fe/MgO/Fe/Al/Ag MTJs as examples, via first-principles calculations, we demonstrate that the partial confinement of Δ1 electron at Al/Fe interface and the full confinement at Fe/MgO interface combine to produce quantum-well resonances in Fe. The quantum-well levels of Fe can be periodically adjusted by two degrees of freedom: Fe and Al thickness. The oscillation period obtained from conductance G↑↑ is 2.13 ML Fe (9 ML Al), close to 2.25 ML Fe (8.33 ML Al) calculated by bcc-Fe (fcc-Al) band. The combination of long and short periods enables quantum-well levels to be finely adjusted. An ultrahigh optimistic TMR effect of 3.05×105\% is achieved. Our results provides a new path for designing and applying quantum-well resonances in spintronics devices.
@article{arxiv.2311.11505,
title = {Quantum-well resonances caused by partial confinement in MgO-based magnetic tunnel junctions},
author = {L. N. Jiang and B. Y. Chi and W. Z. Chen and X. F. Han},
journal= {arXiv preprint arXiv:2311.11505},
year = {2024}
}