Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Nat Commun. 2017 May 22;8:15387. doi: 10.1038/ncomms15387.
A major issue in the development of spintronic memory devices is the reduction of the power consumption for the magnetization reversal. For this purpose, the artificial control of the magnetic anisotropy of ferromagnetic materials is of great importance. Here, we demonstrate the control of the carrier-energy dependence of the magnetic anisotropy of the density of states (DOS) using the quantum size effect in a single-crystal ferromagnetic material, GaMnAs. We show that the mainly twofold symmetry of the magnetic anisotropy of DOS, which is attributed to the impurity band, is changed to a fourfold symmetry by enhancing the quantum size effect in the valence band of the GaMnAs quantum wells. By combination with the gate electric-field control technique, our concept of the usage of the quantum size effect for the control of the magnetism will pave the way for the ultra-low-power manipulation of magnetization in future spintronic devices.
在自旋电子存储器件的发展中，一个主要问题是降低磁化反转所需的功耗。为此，人工控制铁磁材料的磁各向异性非常重要。在这里，我们通过在单晶铁磁材料 GaMnAs 中利用量子尺寸效应，演示了对态密度（DOS）的磁各向异性与载流子能量依赖关系的控制。我们表明，主要由杂质能带引起的 DOS 磁各向异性的两倍旋转对称性通过增强 GaMnAs 量子阱价带中的量子尺寸效应，变为四重旋转对称性。通过与栅极电场控制技术相结合，我们使用量子尺寸效应控制磁性的概念将为未来自旋电子器件中对磁化的超低功耗操控铺平道路。
