Fig. 2
From: Tuning the interplay between nematicity and spin fluctuations in Na1−xLi x FeAs superconductors
75As NMR spectra in Na1−xLi x FeAs for for H || ab. a Central and satellite lines of 75As as a function of doping at a fixed temperature of 60 K at 9.1 T. While the linewidth of the spectra increases with increasing doping, there is no other lines found and the quadrupole frequency νQ remains nearly unchanged. b–f Temperature dependence of the 75As central line as a function of x. For x = 0 and 0.02, the 75As spectrum starts to broaden and shift to higher frequency below TSDW. In contrast, for x ≥ 0.04, neither a significant broadening nor a shift of the line was observed, evidencing the absence of static magnetic moments. An inhomogeneous line broadening below T0 for the intermediate doping x = 0.03 is ascribed to short-range magnetism associated with the charge/orbital ordered phase. The large reduction of the signal intensity below ~10 K is due to bulk superconductivity
