School of Chemistry and Materials Sciences, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China. Hefei, Hefei, 230026, P. R. China.
CAS Key Lab of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science & Technology of China, Hefei, 230026, P. R. China.
Adv Mater. 2023 Apr;35(16):e2209365. doi: 10.1002/adma.202209365. Epub 2023 Mar 8.
Van der Waals (vdW) layered materials with strong magnetocrystalline anisotropy have attracted significant interest as the long-range magnetic order in these systems can survive even when their thicknesses is reduced to the 2D limit. Even though the interlayer coupling between the neighboring magnetic layers is very weak, it has a determining effect on the magnetism of these atomic-thickness materials. Herein, a new 2D ferromagnetic material, namely, non-vdW CuCrSe nanosheets with even-odd-layer-dependent ferromagnetism when laminated from an antiferromagnetic bulk is reported. Monolayer and even-layer CuCrSe exhibit the anomalous Hall effect and a significantly enhanced magnetic ordering temperature of more than 125 K. In contrast, the linear Hall effect exists in the odd-layer samples. Theoretical calculations indicate that the layer-dependent magnetic coupling is attributable to the orbital shift of the Cr atoms in the CrSe layers owing to the Cu-induced breaking of the centrosymmetry. Thus, this work sheds light on the exotic magnetic properties of layered materials that exhibit phenomena beyond weak interlayer interactions.
具有强磁晶各向异性的范德华（vdW）层状材料作为长程磁有序系统引起了极大的关注，因为即使将其厚度减小到 2D 极限，这些系统中的长程磁有序仍然存在。尽管相邻磁性层之间的层间耦合非常弱，但它对这些原子厚度材料的磁性具有决定性的影响。在这里，报道了一种新的二维铁磁材料，即非范德华 CuCrSe 纳米片，当从反铁磁体块体层压时，其具有偶数层和奇数层依赖的铁磁性。单层和偶数层 CuCrSe 表现出反常霍尔效应和超过 125 K 的显著增强的磁有序温度。相比之下，奇数层样品中存在线性霍尔效应。理论计算表明，层依赖的磁耦合归因于 Cr 原子在 CrSe 层中的轨道位移，这是由于 Cu 诱导的中心对称破坏引起的。因此，这项工作揭示了具有超出弱层间相互作用的现象的层状材料的奇异磁性。
