AI 中文总结
研究UAgBi₂材料，通过比热等手段构建相图，利用具有特定传播矢量的方波结构理解多步磁化过程，发现其符合磁魔鬼阶梯，是5\textit{f}电子系统中该阶梯的罕见实例。
AI 中文摘要
具有竞争相互作用的材料通常呈现大量近简并的周期性状态。本文表明层状UAgBi₂存在一系列由磁场和温度诱导的磁转变。基于比热、热膨胀和中子衍射，构建了相图，揭示UAgBi₂中至少有七个近简并磁态。在强易轴各向异性限制磁矩沿c轴的情况下，通过具有不同传播矢量\(\mathbf{k}\)=(0, 0, \textit{k})的方波结构可理解观测到的多步磁化过程。研究结果与轴向次近邻伊辛（ANNNI）模型描述的磁魔鬼阶梯一致，使UAgBi₂成为5\textit{f}电子系统中魔鬼阶梯的罕见实例。
英文摘要
Materials characterized by competing interactions often exhibit a large number of nearly degenerate periodic states. Here we show that layered UAgBi$_2$ hosts a cascade of field- and temperature-induced magnetic transitions. Based on specific heat, thermal expansion, and neutron diffraction, we construct a phase diagram that reveals at least seven nearly degenerate magnetic states in UAgBi$_2$. The observed multi-step magnetization process can be understood by square-wave structures with distinct propagation vectors $\mathbf{k}$=(0, 0, \textit{k}) in the presence of strong easy-axis anisotropy that confines the moments along the \textit{c} axis. Our findings are consistent with a magnetic devil's staircase described by the axial next-nearest neighbor Ising (ANNNI) model and place UAgBi$_2$ as a rare realization of the devil's staircase in a 5\textit{f}-electron system.
