Figure 3
(a) ZF-μSR spectra (using a dilution refrigerator) at representative temperatures (see Supplementary Information Sec. II for the spectra obtained using 4He cryostat). The thick lines behind the data points are curves fitted by using the stretched exponential function (see text). The inset shows the ZF-μSR spectrum measured at 90 mK, which decreases continuously without oscillations up to 20 μs. (b) μSR spectra measured at 90 mK under ZF and representative longitudinal magnetic fields. The inset shows the magnetic field dependence of the muon spin relaxation rate λ B . The blue solid line and gray dashed line are curves fitted by using the power-law and logarithmic equation (see text). (c) Temperature dependence of the muon spin relaxation rate λ. (d) Temperature dependence of the stretching exponent β. The gray solid lines in (c,d) are the guide to eyes.
