Inhomogeneous magnetic order in the archetypical 2D van der Waals magnet CrI3

Two-dimensional (2D) van der Waals (vdW) magnets have become the subject of intense interest due to their rich diversity of optical, electronic and topologically states. CrI3 is a well known example. While the near monolayer limit has been the subject of intense scrutiny, it has become clear that even the bulk material hosts a much richer behaviour than initially assumed. In a recent study combining µSR and other techniques, it was revealed that bulk CrI3 hosts several magnetic phases with distinct transitions. Remarkably, Tc does not correspond to long range order in the full volume but rather to a partial transition. While µSR is able to clarify the local magnetic behaviour, it is unable to provide details on correlation lengths and domain sizes. Here, we aim to quantify the magnetic correlation length associated with the spatially inhomogeneous ferromagnetism in CrI3 using SANS.

二维（2D）范德华（van der Waals, vdW）磁体因其丰富的光学、电子与拓扑态多样性而受到广泛关注，碘化铬（CrI₃）便是其中广为人知的一例。尽管学界此前对近单层极限体系开展了大量细致研究，但如今人们已然意识到，即便块体材料也展现出远超初始假设的丰富物理行为。在一项结合μ子自旋弛豫谱（µSR）与其他实验技术的近期研究中，科研人员发现块体碘化铬存在多个具有不同相变的磁相。值得注意的是，其居里温度（Tc）并不对应体系整体的长程磁有序，而是对应部分区域的相变。尽管μ子自旋弛豫谱能够阐明局域磁行为，却无法给出关联长度与磁畴尺寸的相关细节。本研究旨在借助小角中子散射（SANS），定量表征碘化铬中空间非均匀铁磁性对应的磁关联长度。