Sun Qi-Chao, Song Tiancheng, Anderson Eric, Brunner Andreas, Förster Johannes, Shalomayeva Tetyana, Taniguchi Takashi, Watanabe Kenji, Gräfe Joachim, Stöhr Rainer, Xu Xiaodong, Wrachtrup Jörg
3. Physikalisches Institut, University of Stuttgart, Stuttgart, Germany.
Department of Physics, University of Washington, Seattle, WA, USA.
Nat Commun. 2021 Mar 31;12(1):1989. doi: 10.1038/s41467-021-22239-4.
The emergence of atomically thin van der Waals magnets provides a new platform for the studies of two-dimensional magnetism and its applications. However, the widely used measurement methods in recent studies cannot provide quantitative information of the magnetization nor achieve nanoscale spatial resolution. These capabilities are essential to explore the rich properties of magnetic domains and spin textures. Here, we employ cryogenic scanning magnetometry using a single-electron spin of a nitrogen-vacancy center in a diamond probe to unambiguously prove the existence of magnetic domains and study their dynamics in atomically thin CrBr. By controlling the magnetic domain evolution as a function of magnetic field, we find that the pinning effect is a dominant coercivity mechanism and determine the magnetization of a CrBr bilayer to be about 26 Bohr magnetons per square nanometer. The high spatial resolution of this technique enables imaging of magnetic domains and allows to locate the sites of defects that pin the domain walls and nucleate the reverse domains. Our work highlights scanning nitrogen-vacancy center magnetometry as a quantitative probe to explore nanoscale features in two-dimensional magnets.
原子级薄的范德华磁体的出现为二维磁性及其应用的研究提供了一个新平台。然而，近期研究中广泛使用的测量方法无法提供磁化强度的定量信息，也无法实现纳米级空间分辨率。而这些能力对于探索磁畴和自旋纹理的丰富特性至关重要。在此，我们利用金刚石探针中氮空位中心的单电子自旋进行低温扫描磁测量，明确证实了磁畴的存在，并研究了它们在原子级薄的CrBr₃中的动力学。通过控制磁畴随磁场的演化，我们发现钉扎效应是主要的矫顽力机制，并确定CrBr₃双层的磁化强度约为每平方纳米26玻尔磁子。该技术的高空间分辨率能够对磁畴进行成像，并可定位钉扎畴壁和产生反向畴的缺陷位置。我们的工作突出了扫描氮空位中心磁测量作为探索二维磁体纳米级特征的定量探针的作用。
