Figure 5 : The quantity 1/T1T and the Knight shift.

From: Quantum criticality in electron-doped BaFe2−xNixAs2

Figure 5

(a) Temperature dependence of 1/T1T and (b) the Knight shift K for various x. The solid line is a fitting of . The dashed curve is a fit to K=K0+Ks × exp(−Eg/kBT). The obtained parameters are Eg/kB=620±40, 510±40, 370±30, 365±30, 350±30 and 330±30 K for x=0.05, 0.07, 0.09, 0.10, 0.12 and 0.14, respectively. The solid and dashed arrows indicate Tc and TN, respectively. The error bar for 1/T1T is the s.d. in fitting the nuclear magnetization recovery curve. The error bar for K was estimated by assuming that the spectrum-peak uncertainty equals the point (frequency) interval in measuring the NMR spectra.