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arXiv · 2011.07217

Voltage-controlled magnetic anisotropy under the electronic structure modulation in quantum wells

Qingyi Xiang·Yoshio Miura·Muftah Al-Mahdawi·Thomas Scheike·Xiandong Xu·Yuya Sakuraba·Shinya Kasai·Zhenchao Wen·Hiroaki Sukegawa·Seiji Mitani·Kazuhiro Hono
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Abstract

Voltage-controlled magnetic anisotropy (VCMA) offers an emerging approach to realize energy-efficient magnetization switching in spintronic devices such as magnetic random access memories (MRAMs). Here, we show that manipulating the condensed states, i.e., introducing quantum well (QW) can significantly influence the VCMA in a Cr/Fe-QW/MgAl2O4 based magnetic tunnel junction (MTJ). Only for the MTJ with an even number of Fe atomic layers, we observed a novel A-shaped VCMA curve for a particular QW state, where magnetic anisotropy energy (MAE) reaches a local maximum at zero bias and reduces when applying both positive and negative bias, i.e., a novel bi-polar VCMA effect. Our ab initio calculations demonstrate that the QW states give an additional contribution to perpendicular magnetic anisotropy (PMA), which can explain not only the A-shaped VCMA but also the Fe-layer-number parity dependence of VCMA. The present study suggests that the QW-modulated VCMA should open a new pathway to design VCMA-assisted MRAM.

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Qingyi Xiang, Yoshio Miura, Muftah Al-Mahdawi, Thomas Scheike, Xiandong Xu, Yuya Sakuraba, Shinya Kasai, Zhenchao Wen, Hiroaki Sukegawa, Seiji Mitani, Kazuhiro Hono. 2020-11-14. Voltage-controlled magnetic anisotropy under the electronic structure modulation in quantum wells. https://arxiv.org/abs/2011.07217

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