Zhu Rui, Zhang Wen, Shen Wei, Wong Ping Kwan Johnny, Wang Qixing, Liang Qijie, Tian Zhen, Zhai Ya, Qiu Cheng-Wei, Wee Andrew T S
Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
School of Electronics and Information, Northwestern Polytechnical University, Xi'an 710072, China.
Nano Lett. 2020 Jul 8;20(7):5030-5035. doi: 10.1021/acs.nanolett.0c01149. Epub 2020 Jun 2.
Exchange bias is a physical phenomenon whereby the spins of a ferromagnet are pinned by those of an antiferromagnet, and this phenomenon has played an undisputed role in magnetic data storage. Over the past few decades, this effect has been observed in a variety of antiferromagnet/ferromagnet systems. New aspects of this phenomenon are being discovered. With the increasing interest in van der Waals (vdW) magnets, we address the question whether the effect can exist in magnetic vdW heterostructures. Here, we report exchange-bias fields of over 50 mT in mechanically exfoliated CrCl/FeGeTe heterostructures at 2.5 K, the value of which is highly tunable by the field-cooling process and the heterostructure thickness. We postulate an intuitive picture explaining how the effect arises in this vdW heterostructure, as well as explaining the practical difficulty associated with capturing the effect. This work opens up new routes toward designing spintronic devices made of atomically thin vdW magnets.
交换偏置是一种物理现象，其中铁磁体的自旋被反铁磁体的自旋钉扎，并且这种现象在磁数据存储中发挥了无可争议的作用。在过去几十年中，这种效应已在各种反铁磁体/铁磁体系统中被观察到。该现象的新方面正在被发现。随着对范德华（vdW）磁体的兴趣日益增加，我们探讨了这种效应是否能在磁性vdW异质结构中存在的问题。在此，我们报告了在2.5 K下机械剥离的CrCl/FeGeTe异质结构中超过50 mT的交换偏置场，其值可通过场冷过程和异质结构厚度进行高度调节。我们提出了一个直观的图景，解释了这种效应在这种vdW异质结构中是如何产生的，以及解释了捕捉该效应所涉及的实际困难。这项工作为设计由原子级薄的vdW磁体制成的自旋电子器件开辟了新途径。
