Quantum-well (QW) devices have been extensively investigated in semiconductor structures. More recently, spin-polarized QWs were integrated into magnetic tunnel junctions (MTJs). In this work, we demonstrate the spin-based control of the quantized states in iron 3d-band QWs, as observed in experiments and theoretical calculations. We find that the magnetization rotation in the Fe QWs significantly shifts the QW quantization levels, which modulate the resonant-tunneling current in MTJs, resulting in a tunneling anisotropic magnetoresistance (TAMR) effect of QWs. This QW-TAMR effect is sizable compared to other types of TAMR effect, and it is present above the room-temperature. In a QW MTJ of Cr/Fe/MgAl2O4/top electrode, where the QW is formed by a mismatch between Cr and Fe in the d band with Δ1 symmetry, a QW-TAMR ratio of up to 5.4 % was observed at 5 K, which persisted to 1.2 % even at 380K. The magnetic control of QW transport can open new applications for spin-coupled optoelectronic devices, ultra-thin sensors, and memories.
@article{arxiv.2105.06234,
title = {Quantum-well tunneling anisotropic magnetoresistance above room temperature},
author = {Muftah Al-Mahdawi and Qingyi Xiang and Yoshio Miura and Mohamed Belmoubarik and Keisuke Masuda and Shinya Kasai and Hiroaki Sukegawa and Seiji Mitani},
journal= {arXiv preprint arXiv:2105.06234},
year = {2021}
}