论文标题
$ h $ -t $ t $相位图在2D三角形反铁磁铁ybmggao ybmggao $ _4 $中的持续旋转动力和旋转冷冻的缺失
Persistent spin dynamics and absence of spin freezing in the $H$-$T$ phase diagram of the 2D triangular antiferromagnet YbMgGaO$_4$
论文作者
论文摘要
我们报告了在自旋液体候选者〜ybmggao $ _ {4} $上进行MUON自旋松弛和旋转（$μ$ SR）实验的结果。没有观察到静态磁性$ \ gtrsim0.003μ_b$每yb离子，有序或无序，低于22〜MK，温度的温度低于先前的测量值。观察到持续的（无关）旋转动力学最大为0.20〜K，至少1〜KOE，因此在$ h $ -t $ t $相图的大量区域上扩展了先前的零景$ $ $ SR结果。 10 koE横向场中的骑士移位测量结果显示两条线几乎相等的线。在纵向场中的不均匀性muon去极化，以前以空间不均匀性引起的伸展指数弛豫为特征，与两个指数同样适合，同样相等。我们将这些结果归因于单位细胞中的两个间质若子位点，而不是混乱或其他空间分布。从两个测量的松弛率的比率和计算出的均方根Yb $^{3+} $偶极场的比率之间，可以从候选MUON站点的偶极域中达成一致性。零场数据可以理解为两指数动态弛豫和准确的核双极场的组合。
We report results of muon spin relaxation and rotation ($μ$SR) experiments on the spin-liquid candidate~YbMgGaO$_{4}$. No static magnetism $\gtrsim 0.003μ_B$ per Yb ion, ordered or disordered, is observed down to 22~mK, a factor of two lower in temperature than previous measurements. Persistent (temperature-independent) spin dynamics are observed up to 0.20~K and at least 1~kOe, thus extending previous zero-field $μ$SR results over a substantial region of the $H$-$T$ phase diagram. Knight shift measurements in a 10-kOe transverse field reveal two lines with nearly equal amplitudes. Inhomogeneous muon depolarization in a longitudinal field, previously characterized by stretched-exponential relaxation due to spatial inhomogeneity, is fit equally well with two exponentials, also of equal amplitudes. We attribute these results to two interstitial muon sites in the unit cell, rather than disorder or other spatial distribution. Further evidence for this attribution is found from agreement between the ratio of the two measured relaxation rates and calculated mean-square local Yb$^{3+}$ dipolar fields at candidate muon sites. Zero-field data can be understood as a combination of two-exponential dynamic relaxation and quasistatic nuclear dipolar fields.
