Crystal Growth, Structure, and Magnetism of the 2D Spin 1/2 Triangular Lattice Material Rb3Yb(PO4)2

The single-crystal growth, crystal structure, heat capacity, and anisotropic magnetization characterization of Rb3Yb­(PO4)2, a Yb-based triangular lattice material, are presented. Single-crystal X-ray diffraction shows that Rb3Yb­(PO4)2 exhibits [Yb­(PO4)]∞ layers, with the Yb in an ordered plane of equilateral triangles. One phosphate group oxygen that is not a near neighbor of the magnetic Yb displays positional disorder. The temperature-dependent magnetization is anisotropic, with no long-range magnetic ordering observed for temperatures down to 50 mK. The low temperature heat capacity in the presence of an applied magnetic field is fitted very well by a Schottky anomaly with a linear magnetic-field-dependent gap between the ground and excited state energies. At 1.8 K, no magnetic transitions are seen for applied fields up to 90 kOe. Our results suggest that Rb3Yb­(PO4)2 is a good candidate for displaying frustrated magnetism at low temperatures.本文报道了基于镱（Yb）的三角晶格材料Rb₃Yb(PO₄)₂的单晶生长、晶体结构、热容及各向异性磁化表征结果。单晶X射线衍射分析显示，Rb₃Yb(PO₄)₂具有[Yb(PO₄)]∞层状结构，Yb离子位于有序排布的等边三角形平面内。有一个不与磁性Yb离子近邻的磷酸根基团氧原子存在位置无序现象。该材料的温变磁化强度表现出各向异性，在低至50毫开（mK）的温度范围内均未观测到长程磁有序现象。在外加磁场下的低温热容可通过肖特基反常（Schottky anomaly）进行极佳拟合，其基态与激发态能级间的能隙随磁场呈线性变化。在1.8 K温度下，当外加磁场最高至90千奥斯特（kOe）时，未观测到任何磁相变。本研究结果表明，Rb₃Yb(PO₄)₂是一种有望在低温下展现阻挫磁性的优质候选材料。