Bagani Kousik, Vervelaki Andriani, Jetter Daniel, Devarakonda Aravind, Tschudin Märta A, Gross Boris, Chica Daniel G, Broadway David A, Dean Cory R, Roy Xavier, Maletinsky Patrick, Poggio Martino
Department of Physics, University of Basel, 4056 Basel, Switzerland.
Department of Physics, Columbia University, New York, New York 10027, United States.
Nano Lett. 2024 Oct 4. doi: 10.1021/acs.nanolett.4c03919.
Two-dimensional materials are extraordinarily sensitive to external stimuli, making them ideal for studying fundamental properties and for engineering devices with new functionalities. One such stimulus, strain, affects the magnetic properties of the layered magnetic semiconductor CrSBr to such a degree that it can induce a reversible antiferromagnetic-to-ferromagnetic phase transition. Using scanning SQUID-on-lever microscopy, we directly image the effects of spatially inhomogeneous strain on the magnetization of layered CrSBr, as it is polarized by a field applied along its easy axis. The evolution of this magnetization and the formation of domains is reproduced by a micromagnetic model, which incorporates the spatially varying strain and the corresponding changes in the local interlayer exchange stiffness. The observed sensitivity to small strain gradients along with similar images of a nominally unstrained CrSBr sample suggest that unintentional strain inhomogeneity influences the magnetic behavior of exfoliated samples.
二维材料对外部刺激极为敏感，这使其成为研究基本性质以及制造具有新功能器件的理想选择。应变就是这样一种刺激，它对层状磁性半导体CrSBr的磁性能影响极大，以至于能诱发可逆的反铁磁到铁磁相变。利用扫描杠杆式超导量子干涉仪显微镜，我们直接成像了空间不均匀应变对层状CrSBr磁化的影响，此时CrSBr沿其易轴方向被磁场极化。这种磁化的演变和磁畴的形成由一个微磁模型再现，该模型纳入了空间变化的应变以及局部层间交换刚度的相应变化。观察到的对小应变梯度的敏感性以及名义上未受应变的CrSBr样品的类似图像表明，无意的应变不均匀性会影响剥离样品的磁行为。
