论文标题
超霍尼晶格中的慢自旋动力学[（C2H5）3NH] 2CU2（C2O4）3通过1H NMR研究揭示
Slow spin dynamics in the hyper-honeycomb Lattice [(C2H5)3NH]2Cu2(C2O4)3 revealed by 1H NMR studies
论文作者
论文摘要
我们报告了在三维超霍尼comb晶格化合物[（C $ _2 $ _2 $ _2 $ _5 $）$ _ 3 $ _ 3 $ nh] $ _ 2 $ _ 2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ __ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccced a磁易感性$χ$和$^1 $ h核磁共振（NMR）测量结果Cu $^{2+} $（$ s $ = 1/2）之间的抗铁磁（AFM）交换耦合的平均值被确定为$ J $〜$〜$〜$ \ sim $ 〜50 K，从$χ$测量值中。尽管NMR线在低于1 K的低温下变得较宽，但尚未观察到$ t $ = 50 mk $ t $ = 50 mk。在1 K以下观察到的NMR光谱的扩展表明，CU旋转力矩保持在该温度下，这表明非蜘蛛网基态态度。高于20 K的温度和磁场的依赖性通过顺磁热自旋波动很好地解释了Cu $^{2+} $ spins的波动频率高于MHz顺序的NMR频率。但是，在低温下观察到Cu $^{2+} $旋转波动的明确签名，其中1/$ t_1 $显示出热激活的行为。旋转激发差距的大小的磁场依赖性表明，CCCO的磁性行为在低温下被描述为AFM链。
We report the results of magnetic susceptibility $χ$ and $^1$H nuclear magnetic resonance (NMR) measurements on a three-dimensional hyper-honeycomb lattice compound [(C$_2$H$_5$)$_3$NH]$_2$Cu$_2$(C$_2$O$_4$)$_3$ (CCCO). The average value of the antiferromagnetic (AFM) exchange coupling between the Cu$^{2+}$ ($S$ = 1/2) spins was determined to be $J$~$\sim$~50 K from the $χ$ measurements. No long-range magnetic ordering has been observed down to $T$ = 50 mK, although NMR lines become slightly broader at low temperatures below 1 K. The broadening of the NMR spectrum observed below 1 K reveals that the Cu spin moments remain at this temperature, suggesting a non-spin-singlet ground state. The temperature and magnetic field dependence of 1/$T_1$ at temperatures above 20 K is well explained by paramagnetic thermal spin fluctuations where the fluctuation frequency of Cu$^{2+}$ spins is higher than the NMR frequency of the order of MHz. However, a clear signature of the slowing down of the Cu$^{2+}$ spin fluctuations was observed at low temperatures where 1/$T_1$ shows a thermally-activated behavior. The magnetic field dependence of the magnitude of the spin excitation gap suggests that the magnetic behaviors of CCCO are characterized as an AFM chain at low temperatures.
