发表机构
New Cornerstone Lab, Center for Correlated Matter and School of Physics, Zhejiang University; Institute for Advanced Materials, Hubei Normal University; Institute of Fundamental and Transdisciplinary Research, Zhejiang University; Institute for Advanced Study in Physics, Zhejiang University; State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University; Collaborative Innovation Center of Advanced Microstructures, Nanjing（浙江大学关联物质中心物理学院新基石实验室; 湖北师范大学先进材料研究所; 浙江大学基础与交叉研究院; 浙江大学物理学高等研究院; 浙江大学硅与先进半导体材料国家重点实验室; 南京先进微结构协同创新中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过电阻率、比热和磁化测量，系统研究了Ce$_5$RhGe$_2$和Ce$_5$IrGe$_2$单晶的磁性，发现前者为居里温度约11.5 K的铁磁体，后者在12.7 K和11.8 K发生两次磁相变并呈现亚铁磁基态。
AI 中文摘要
通过电阻率、比热和磁化强度测量，对Ce$_5$RhGe$_2$和Ce$_5$IrGe$_2$单晶进行了系统研究。与Ce$_5$CoGe$_2$一起，这三种化合物均结晶为正交晶系\emph{Pnma}结构，晶格参数从Co到Rh再到Ir单调增加，与负化学压力的效应一致。沿三个主晶轴的磁化强度测量表明，在整个系列中，\emph{a}轴为易磁化方向。Ce$_5$RhGe$_2$表现出铁磁有序，居里温度约为11.5 K，其磁行为与Ce$_5$CoGe$_2$非常相似。相比之下，Ce$_5$IrGe$_2$在$T_{\rm M1}=12.7$ K和$T_{\rm M2}=11.8$ K处经历两次连续的磁相变，并且在磁场下存在多个变磁转变，导致在饱和磁化强度$M_{\rm s}$的分数处出现磁化平台，约为$M_{\rm s}/5$和$M_{\rm s}/3$。沿易磁化轴的低场变磁转变随温度降低而移至更低场，最终在零场附近观察到明显的磁滞回线，表明Ce$_5$IrGe$_2$在最低测量温度下表现出亚铁磁基态。
英文摘要
Single crystals of Ce$_5$RhGe$_2$ and Ce$_5$IrGe$_2$ have been systematically investigated by electrical resistivity, specific heat, and magnetization measurements. Together with Ce$_5$CoGe$_2$, all three compounds crystallize in the orthorhombic \emph{Pnma} structure, with the lattice parameters increasing monotonically from Co to Rh to Ir, consistent with the effect of negative chemical pressure. Magnetization measurements along the three principal crystallographic axes identify the \emph{a} axis as the easy magnetization direction throughout the series. Ce$_5$RhGe$_2$ exhibits ferromagnetic ordering with a Curie temperature of approximately 11.5 K and shows magnetic behavior closely resembling that of Ce$_5$CoGe$_2$. In contrast, Ce$_5$IrGe$_2$ undergoes two successive magnetic transitions at $T_{\rm M1}=12.7$ K and $T_{\rm M2}=11.8$ K, and there are multiple metamagnetic transitions under magnetic fields, giving rise to magnetization plateaus at fractions of the saturation magnetization $M_{\rm s}$ of approximately $M_{\rm s}/5$ and $M_{\rm s}/3$. The low-field metamagnetic transition along the easy axis shifts to lower field with decreasing temperature, and eventually a pronounced hysteresis loop is observed about zero-field, establishing that Ce$_5$IrGe$_2$ exhibits a ferrimagnetic ground state at the lowest measured temperatures.
Comments8 pages, 6 figures
