High-field 1H-NMR study around a 1/4 plateau of quantum spin dimer system NH4CuCl3

8th International Conference on Highly Frustrated Magnetism 2016

Matsui, K.^1 ; Fujisawa, M.^2 ; Tanaka, H.^2 ; Scheuermann, R.^3 ; Goto, T.^1

Physics Division, Sophia University, Tokyo

102-8544, Japan^1

Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo

152-8551, Japan^2

Paul Scherrer Institute, Villigen PSI

CH-5232, Switzerland^3

关键词: High-field regions;    Hyperfine field;    Liquid-solid transition;    Magnetic orders;    Multiple-peak;    NMR studies;    Plateau state;    Quantum spin-dimer systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/828/1/012011/pdf
DOI  :  10.1088/1742-6596/828/1/012011

来源: IOP

【 摘 要 】

We have investigated high-field TF-μ SR and1H-NMR on the S = 1/2 three dimensional spin dimer system NH4CuCl3, which shows a magnetic order at TN= 1.29 K under zero field and the two-stepped plateaus in high field regions HC1= 5.0 T - HC2= 12.8 T and HC3= 17.9 T - HC4= 24.7 T. Both probes showed spectra containing multiple peaks corresponding to different hyperfine fields, demonstrating the existence of magnetically inequivalent dimers in a unit cell. In the slope-state field region H C1, the existence of magnetic order was confirmed by the splitting in some of the NMR peaks. The whole width of NMR and μ SR spectra increased with increasing field, and no drastic change in their profile was observed at HC1. This indicates that the change in the spin state is continuous on entering the plateau state, and that no liquid-solid transition of magnons takes place at the phase boundary.