RAlGe（R = Y, Gd-Tm, Lu）的各向异性磁性与输运性质
Anisotropic Magnetic and Transport Properties of RAlGe (R = Y, Gd-Tm, Lu)
- Ames National Laboratory（艾姆斯国家实验室）
- Department of Physics and Astronomy, Iowa State University（爱荷华州立大学物理与天文系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究生长了RAlGe（R = Y, Gd-Tm, Lu）单晶，表征了其反铁磁有序、晶体场效应及变磁转变，发现各向异性磁性与输运性质，并观察到YAlGe中的de Haas-van Alphen振荡。
AI中文摘要：
我们生长了R = Y, Gd-Tm, Lu的RAlGe家族单晶，并通过粉末X射线衍射、变温比热测量以及变温和变场电阻与磁化强度测量对其进行了表征。这些RAlGe材料结晶为正交晶系Cmcm晶体结构，其中R原子占据具有$m$2$m$点对称性的位置。我们发现，当R为携带磁矩的稀土原子时，RAlGe材料在$T_{\ ext{N}}$从5 K（TmAlGe）到39 K（TbAlGe）的范围内发生反铁磁有序。对于R = Tb-Ho，还在6-8 K范围内检测到第二个较低温度的反铁磁转变，但对于R = Er, Tm，在1.8 K以上未观察到较低温度转变。R = Tb-Tm成员显示出强晶体场效应影响物理性质的证据，其中晶体场有利于R = Tb-Ho的易$a$轴和R = Er, Tm的易$b$轴。在这些化合物中，DyAlGe和TmAlGe表现出强单轴行为。在T = 2 K时，对于R = Tb-Ho，当外场沿$a$轴施加时观察到丰富的变磁转变，而对于R = Er和Tm，当磁场沿$b$轴时观察到单一的变磁转变（高达70 kOe）。所有RAlGe材料均表现出金属输运行为，并在2 K时具有高达60-150%的中等正磁电阻，叠加在变磁特征之上。对无磁矩的YAlGe进行的变场磁化强度测量显示出清晰的de Haas-van Alphen振荡，表明费米面包含小的、高迁移率口袋。
英文摘要：
We grew single crystals of the RAlGe family for R = Y, Gd-Tm, Lu and characterized them with powder X-ray diffraction, temperature dependent specific heat measurements as well as temperature and field dependent resistance and magnetization measurements. These RAlGe materials crystallize in an orthorhombic Cmcm crystal structure in which the R atoms occupy a position with $m$2$m$ point symmetry. We find that when R is a moment bearing rare earth atom, the RAlGe materials order antifferomagnetically at $T_{\text{N}}$ ranging from 5 K (TmAlGe) to 39 K (TbAlGe). A second, lower temperature antiferromagnetic transition is also detected in the range 6-8 K for R = Tb-Ho, but no lower transition is observed (for T above 1.8 K) for R = Er, Tm. The R = Tb-Tm members show evidence for strong crystal field effects influencing the physical properties, where the crystal field favors an easy $a$-axis for R = Tb-Ho and an easy $b$-axis for R = Er, Tm. Of these compounds, strongly uniaxial behavior is observed for DyAlGe and TmAlGe. At T = 2 K, rich metamagnetism is observed when the external field is applied along the $a$-axis for R = Tb--Ho, whereas a single metamagnetic transition is observed (up to 70 kOe) with the field along the $b$-axis when R = Er and Tm. All RAlGe materials show metallic transport behavior and have moderate positive magnetoresistance up to 60-150 % at 2 K superimposed on top of metamagnetic features. The field dependent magnetization measurements on non-moment bearing YAlGe show clear de Haas-van Alphen oscillations, indicating the Fermi surface includes small, high mobility pockets.
