Jiang Shengwei, Shan Jie, Mak Kin Fai
Department of Physics and School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
Department of Physics, The Pennsylvania State University, University Park, PA, USA.
Nat Mater. 2018 May;17(5):406-410. doi: 10.1038/s41563-018-0040-6. Epub 2018 Mar 12.
Controlling magnetism by purely electrical means is a key challenge to better information technology . A variety of material systems, including ferromagnetic (FM) metals, FM semiconductors , multiferroics and magnetoelectric (ME) materials, have been explored for the electric-field control of magnetism. The recent discovery of two-dimensional (2D) van der Waals magnets has opened a new door for the electrical control of magnetism at the nanometre scale through a van der Waals heterostructure device platform . Here we demonstrate the control of magnetism in bilayer CrI, an antiferromagnetic (AFM) semiconductor in its ground state , by the application of small gate voltages in field-effect devices and the detection of magnetization using magnetic circular dichroism (MCD) microscopy. The applied electric field creates an interlayer potential difference, which results in a large linear ME effect, whose sign depends on the interlayer AFM order. We also achieve a complete and reversible electrical switching between the interlayer AFM and FM states in the vicinity of the interlayer spin-flip transition. The effect originates from the electric-field dependence of the interlayer exchange bias.
通过纯电学手段控制磁性是实现更好的信息技术的关键挑战。人们已经探索了多种材料体系，包括铁磁（FM）金属、FM半导体、多铁性材料和磁电（ME）材料，用于电场对磁性的控制。二维（2D）范德华磁体的最新发现，通过范德华异质结构器件平台为纳米尺度下磁性的电学控制打开了一扇新的大门。在此，我们展示了通过在场效应器件中施加小的栅极电压以及使用磁圆二色性（MCD）显微镜检测磁化强度，来控制双层CrI（一种基态为反铁磁（AFM）的半导体）中的磁性。施加的电场会产生层间电势差，这会导致一个大的线性ME效应，其符号取决于层间AFM序。我们还在层间自旋翻转转变附近实现了层间AFM态和FM态之间的完全且可逆的电开关。该效应源于层间交换偏置对电场的依赖性。
