AI 中文总结
本文通过磁化、热容和非弹性中子散射等测量，研究了新型Nd基超kagome反铁磁体Nd₃Li₃W₂O₁₂的磁性质与晶体电场方案，确定其低温为Kramer双重态基态。
AI 中文摘要
基于稀土的石榴石为研究超kagome晶格中阻挫驱动的磁性质提供了可行平台。本文中，我们通过磁化、热容和非弹性中子散射（INS）测量，对一种属于石榴石家族的新型Nd³⁺基超kagome反铁磁体Nd₃Li₃W₂O₁₂的磁性质及晶体电场（CEF）方案开展了综合研究。磁化测量显示其以反铁磁相互作用为主，低温居里-外斯温度θ_CW^LT≈-0.2K。磁场下的磁热容数据中观测到两个宽峰，暗示因CEF效应产生的多能级肖特基反常，并呈现两步磁熵释放。温度低至0.1K时未观测到磁长程有序。通过INS实验探测到具有D₂点群对称性的Nd³⁺（J=9/2）离子的CEF激发，表现为非色散激发，对应CEF能级间的跃迁。对不同温度下INS谱的同时拟合，实现了CEF哈密顿量及 Kramer 双重态能量本征值的绘制。利用所得CEF参数的模拟重现了实验磁 susceptibility、磁等温线及磁热容数据。热力学性质与INS推导的晶体场方案证实，低温下为具有有效自旋J_eff=1/2的Kramer双重态基态。
英文摘要
Rare-earth based garnets provide a viable platform for studying the frustrated driven magnetic properties of the hyperkagome lattices. Herein, we report a comprehensive study of the magnetic properties and crystal electric field (CEF) scheme of a new Nd$^{3+}$ based hyperkagome antiferromagnet, Nd$_3$Li$_3$W$_2$O$_{12}$ belonging to the garnet family via magnetization, heat capacity, and inelastic neutron scattering (INS) measurements. Magnetization measurement reveals a dominant antiferromagnetic interaction with a low temperature Curie-Weiss temperature $θ_{\rm CW}^{\rm LT} \simeq -0.2$ K. Two broad maxima are observed in the magnetic heat capacity data under magnetic fields, implying multilevel Schottky anomalies due to the effect of CEF and display a two-step magnetic entropy release. No magnetic long-range order is observed down to 0.1 K. The CEF excitations of the Nd$^{3+}$ ($J=9/2$) ion with $D_2$ point group symmetry, probed via INS experiments, show non-dispersive excitations characterizing the transitions among the CEF energy levels. The simultaneous fit of the INS spectra at different temperatures enabled the mapping of the CEF Hamiltonian and the energy eigenvalues of the Kramers' doublets. The simulation using the obtained CEF parameters reproduces the experimental magnetic susceptibility, magnetic isotherms, and magnetic heat capacity data. The thermodynamic properties and INS-derived crystal-field scheme confirm a Kramers' doublet ground state with an effective spin $J_{\rm eff} = 1/2$ at low temperatures.
Comments13 pages, 7 figures, 56 references
