Investigating the complex magnetic landscape in 2D kagome magnet single crystals using single crystal neutron diffraction

The LnTi3Bi4 [Ln: Rare earth element] family of compounds is structurally characterized by a slightly distorted Ti double kagome layer, which is sandwiched between Ln Bi double layers. In this configuration, the rare-earth (Ln) atoms form highly anisotropic quasi-one-dimensional zigzag chains. The primary appeal of this family lies in its highly tunable magnetism, which can be precisely controlled through rare-earth engineering to adjust the magnetic state from nonmagnetic to ferromagnetic (FM) or antiferromagnetic (AFM). NdTi3Bi4 and TbTi3Bi4, are part of this newly discovered 2D kagome lattice material family. NdTi3Bi4 exhibits a complex magnetic transition at Tc=8.8 K, while TbTi3Bi4 exhibits three magnetic transitions at TN~ 3, 20 and 24 K. Here we proposed to investigate a detail magnetic structure across these transitions using single crystal neutron diffraction study on SXD. The results of the proposed study are important to understand the complex magnetism of these compounds.

LnTi₃Bi₄[Ln：稀土元素（Rare earth element）]系列化合物的结构特征为存在轻微畸变的钛双层笼目（kagome）层，该层夹在Ln-Bi双层之间。在此结构构型中，稀土（Ln）原子形成了高度各向异性的准一维锯齿形链状结构。该系列化合物的核心研究价值在于其具备高度可调谐的磁学特性：可通过稀土元素工程化手段精准调控，使磁态从非磁性态切换至铁磁（FM）或反铁磁（AFM）状态。NdTi₃Bi₄与TbTi₃Bi₄均属于这一新发现的二维笼目晶格材料系列。NdTi₃Bi₄在Tc=8.8 K处表现出复杂的磁相变行为，而TbTi₃Bi₄则在TN≈3 K、20 K与24 K处存在三次磁相变。本研究拟通过在SXD衍射仪上开展的单晶中子衍射实验，对上述相变过程中的精细磁结构进行表征。本项研究的预期结果将有助于深入理解这类化合物的复杂磁学行为。