发表机构
Spallation Neutron Source Science Center; Institute of High Energy Physics, Chinese Academy of Sciences (CAS); Guangdong Provincial Key Laboratory of Extreme Conditions（散裂中子源科学中心; 中国科学院高能物理研究所; 广东省极端条件重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用小角中子散射探测体相TbMn6Sn6单晶，在自旋重取向转变区间未发现长程有序斯格明子晶格，而是观察到各向异性二重对称低Q散射，其演变与磁各向异性和场几何相关，支持条纹或畴状纹理的存在。
AI 中文摘要
TbMn6Sn6是一种中心对称的亚铁磁性kagome金属，兼具拓扑电子态、强磁各向异性以及接近室温的自旋重取向转变（SRT）。对薄样品的实空间成像研究已揭示，在自旋重取向区间内存在螺旋条纹、双斯格明子状纹理以及斯格明子气泡状结构。此类局域纹理是否发展为体相长程有序的斯格明子晶格，仍悬而未决。本文报道了对体相TbMn6Sn6单晶介观尺度磁性进行探测的小角中子散射（SANS）实验结果。在所探索的条件下，我们未观察到指示长程有序斯格明子晶格的六重对称SANS布拉格图案。相反，主要的磁响应是一种各向异性的二重对称低Q散射分量，其强度分布和场依赖性在自旋重取向区间内发生显著演变。在零场下，一个宽且水平拉长的低Q信号在TSR以上出现，并在体系接近顺磁态时减弱。在345 K且H || b的条件下，该信号弥散，并在约700 Oe以下被迅速抑制。相比之下，在310 K且H || c、接近TSR的条件下，响应更为集中且呈线状，并持续至更高场。这些扫描之间的对比可能反映了接近TSR时快速演变的磁各向异性与场几何构型的综合效应。因此，我们的结果确立了自旋重取向区间内体相各向异性介观尺度磁响应的存在，与实空间成像所报道的条纹或畴相关纹理一致，但并未唯一确定其实空间形态。
英文摘要
TbMn6Sn6 is a centrosymmetric ferrimagnetic kagome metal that combines topological electronic states with strong magnetic anisotropy and a near-room-temperature spin-reorientation transition (SRT). Real-space imaging studies of thin specimens have revealed helical stripes, biskyrmion-like textures, and skyrmion-bubble-like structures in the spin-reorientation regime. Whether such local textures develop into a bulk long-range-ordered skyrmion lattice remains unresolved. Here we present small-angle neutron scattering (SANS) results probing the mesoscale magnetism of a bulk TbMn6Sn6 single crystal. We observe no sixfold SANS Bragg pattern indicative of a long-range-ordered skyrmion lattice under the explored conditions. Instead, the dominant magnetic response is an anisotropic twofold low-Q scattering component whose intensity distribution and field dependence evolve markedly across the spin-reorientation regime. In zero field, a broad and horizontally elongated low-Q signal develops above TSR and weakens as the system approaches the paramagnetic state. At 345 K with H || b, the signal is diffuse and is suppressed rapidly below about 700 Oe. By contrast, at 310 K with H || c, close to TSR, the response is more concentrated and line-shaped and persists to higher fields. The contrasts between these scans likely reflect the combined effects of rapidly evolving magnetic anisotropy near TSR and the field geometry. Our results therefore establish a bulk anisotropic mesoscale magnetic response across the spin-reorientation regime, consistent with stripe- or domain-related textures reported by real-space imaging, while not uniquely identifying their real-space morphology.
