Laboratoire de Physique des Solides, Université Paris-Sud 11, UMR CNRS 8502, 91405 Orsay, France.
Phys Rev Lett. 2012 Sep 14;109(11):117203. doi: 10.1103/PhysRevLett.109.117203. Epub 2012 Sep 11.
We present local probe results on the honeycomb lattice antiferromagnet Ba(3)CuSb(2)O(9). Muon spin relaxation measurements in a zero field down to 20 mK show unequivocally that there is a total absence of spin freezing in the ground state. Sb NMR measurements allow us to track the intrinsic susceptibility of the lattice, which shows a maximum at around 55 K and drops to zero in the low-temperature limit. The spin-lattice relaxation rate shows two characteristic energy scales, including a field-dependent crossover to exponential low-temperature behavior, implying gapped magnetic excitations.
我们呈现了关于蜂窝状反铁磁体 Ba(3)CuSb(2)O(9) 的局域探针结果。在零场下低至 20 mK 的μ子自旋弛豫测量明确表明，基态中没有自旋冻结。Sb NMR 测量允许我们跟踪晶格的固有磁化率，它在大约 55 K 处达到最大值，并在低温极限下降至零。自旋晶格弛豫率显示出两个特征能量尺度，包括与场相关的指数低温行为的交叉，这意味着存在带隙的磁激发。
