论文标题
j_eff的晶体生长，磁性和磁化特性
Crystal growth, magnetic, and magnetocaloric properties of J_eff = 1/2 quantum antiferromagnet CeCl_3
论文作者
论文摘要
我们使用改良的Bridgman Stockbarger方法在红外图像炉中报告了CECL3的高质量单晶的生长。使用单晶/粉末X射线衍射，LAUE X射线衍射，拉曼光谱，磁化和热容量探针来表征生长的晶体。 CECL3在具有弱三角变形的六边形结构中结晶。 300 K处的拉曼光谱在106.8、181.2、189、213和219.7 avaimbers展示了五个，明显可分辨的声子模式。磁敏感性显示出较大的各向异性，在垂直方向上具有较大的峰值，这是使用晶体场理论解释的。 CECL3中的晶体场将Ce3+的J = 5/2歧管分解为三个Kramers双重杆，从而产生了良好的基态。在特定的热量中，未检测到在2 K上方的磁顺序。但是，在非零字段中，低温比热变化发生了巨大变化，在30 KOE的中等场下显示了2.5 K的峰值。 CE-CE交换，晶体场基态的较大CE矩以及明显的各向异性是实现高磁环的成分。在50 KOE到60 KOE不等的田野中，观察到23 j/kg/k的最大熵变化。这些值可与某些最佳基于GD的磁电材料相媲美，这表示CECL3作为磁冷却剂的潜力。
We report growth of high-quality single crystals of CeCl3 using a modified Bridgman Stockbarger method in an infrared image furnace. The grown crystals are characterized using single-crystal/powder X-ray diffraction, Laue X-ray diffraction, Raman spectroscopy, magnetization, and heat capacity probes. CeCl3 crystallizes in a hexagonal structure with a weak trigonal distortion. The Raman spectrum at 300 K showcases five, clearly resolvable, phonon modes at 106.8, 181.2, 189, 213, and 219.7 wavenumbers. The magnetic susceptibility show a large anisotropy with a broad peak in the perpendicular orientation, which is explained using the crystal field theory. The crystal field in CeCl3 splits the J = 5/2 manifold of Ce3+ into three Kramers doublets, resulting in a well-isolated ground state. In the specific heat, no magnetic ordering is detected above 2 K. However, in non-zero fields the low-temperature specific heat changes dramatically, showcasing a peak at 2.5 K under a moderate field of 30 kOe. The weak Ce-Ce exchange, large Ce moment in the crystal field ground state, and significant anisotropy are ingredients for realizing a high magnetocaloric effect. A maximum entropy change of 23 J/Kg/K is observed near 2.5 K in fields ranging from 50 kOe to 60 kOe. These values are comparable to some of the best Gd-based magnetocaloric materials, signifying the potential of CeCl3 as a magnetic coolant.
