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arXiv · 2105.06234

Quantum-well tunneling anisotropic magnetoresistance above room temperature

Muftah Al-Mahdawi·Qingyi Xiang·Yoshio Miura·Mohamed Belmoubarik·Keisuke Masuda·Shinya Kasai·Hiroaki Sukegawa·Seiji Mitani
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Abstract

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/MgAl$_2$O$_4$/top electrode, where the QW is formed by a mismatch between Cr and Fe in the $d$ band with $\Delta_1$ 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.

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Muftah Al-Mahdawi, Qingyi Xiang, Yoshio Miura, Mohamed Belmoubarik, Keisuke Masuda, Shinya Kasai, Hiroaki Sukegawa, Seiji Mitani. 2021-05-13. Quantum-well tunneling anisotropic magnetoresistance above room temperature. https://doi.org/10.1103/physrevb.103.l180408

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