Author:
Shi 史 Xinyu 昕雨,Cui 崔 Yi 祎,Shangguan 上 Yanyan 官艳艳,Xu 徐 Xiaoyu 霄宇,Wu 吴 Zhanlong 占龙,Hu 胡 Ze 泽,Li 李 Shuo 硕,Du 杜 Kefan 柯帆,Chen 陈 Ying 颖,Ma 马 Long 龙,Liu 刘 Zhengxin 正鑫,Wen 温 Jinsheng 锦生,Zhang 张 Jinshan 金珊,Yu 于 Weiqiang 伟强
Abstract
Abstract
We perform 23Na nuclear magnetic resonance (NMR) and magnetization measurements on an S = 1, quasi-2D honeycomb lattice antiferromagnet Na3Ni2BiO6. A large positive Curie–Weiss constant of 22.9 K is observed. The NMR spectra at low fields are consistent with a zigzag magnetic order, indicating a large easy-axis anisotropy. With the field applied along the c
* axis, the NMR spectra confirm the existence of a 1/3-magnetization plateau phase between 5.1 T and 7.1 T. The transition from the zigzag order to the 1/3-magnetization plateau phase is also found to be a first-order type. A monotonic decrease of the spin gap is revealed in the 1/3-magnetization plateau phase, which reaches zero at a quantum critical field H
C ≈ 8.35 T before entering the fully polarized phase. These data suggest the existence of exchange frustration in the system along with strong ferromagnetic interactions, hosting the possibility for Kitaev physics. Besides, well below the ordered phase, the 1/T
1 at high fields shows either a level off or an enhancement upon cooling below 3 K, which suggests the existence of low-energy fluctuations.