Fig. 4
From: Tuning the interplay between nematicity and spin fluctuations in Na1−xLi x FeAs superconductors
Spin–lattice relaxation rates as a function of temperature and doping. a, b The spin–lattice relaxation rate divided by temperature, (T1T)−1, measured at 9.1 T perpendicular and parallel to c, respectively. For x = 0 and 0.02, the SDW transitions were identified by the sharp peak of (T1T)−1 at TSDW. Similar sharp transitions were observed for larger dopings (x ≥ 0.03) at temperatures denoted by T0, without an indication of long range SDW order. The comparison between a and b reveals that the strong anisotropy of spin fluctuations persists up to x = 0.06. c Comparison between the (T1T)−1 data for x = 0.02 and x = 0.03 obtained with H || ab. The data for x = 0.02 are offset vertically for clarity. It shows that T0 for x = 0.03 is higher than TSDW for x = 0.02, but nearly coincides with Tnem obtained by resistivity (see Fig. 1)
