Fig. 2: NMR spectra and spin-lattice relaxation rates of TmMgGaO4.
From: Evidence of the Berezinskii-Kosterlitz-Thouless phase in a frustrated magnet
a 69Ga NMR spectra at different temperatures under a 3 T in-plane field, with zero frequency corresponding to γH = 30.692 MHz. Data are shifted vertically for clarity. At high temperatures, the spectra are roughly symmetric, whereas for T ≤ 2 K, a shoulder-like structure can be resolved on the left side of the main peak. b NMR hyperfine shift \({}^{69}{K}_{n}=(\bar{f}/\gamma H-1)\times 100 \%\) as a function of temperature, where \(\bar{f}\) is the average frequency of each spectrum. c NMR spin-lattice relaxation rate 1/69T1 vs. temperature measured under in-plane fields of 3 T and 1 T. A plateau-like feature, characterizing strong magnetic fluctuations, is observed between TL ≃ 0.9 K (lower-BKT transition) and TU ≃ 1.9 K (upper BKT transition). d 1/T1 data computed from the dynamical spin–spin correlation function with contributions from all momentum points [c.f., Eq. (3) and see the hyperfine form factor in Supplementary Note 2] in the Brillouin zone (left scale) and from K′ point in the vicinity of the K point (right scale), through large-scale QMC simulations (see “Methods”).
