Characteristic Timescales of the Local Moment Dynamics in Hund's Metals

We study the characteristic timescales of the fluctuating local moments in Hund's metal systems for different degrees of correlation. By analyzing the dynamical spin susceptibility in the real-time domain, we determine the timescales controlling oscillation and damping of on-site fluctuations-a crucial factor for the detection of local moments with different experimental probes. We apply this procedure to different families of iron pnictides or chalcogenides, explaining the material trend in the discrepancies reported between experimental and theoretical estimates of their magnetic moments.