Impact of Disorder on Microscopic Superconducting and Normal‐State Responses in a Kagome Metal

ABSTRACT In , Ta substitution suppresses charge order while nearly doubling superconducting transition temperature . Pronounced diffuse scattering reveals a highly disordered charge‐ordered state. We investigated the impact of this disorder on the superconducting and normal‐state properties using depth‐resolved, magnetic‐field– and pressure‐tuned muon‐spin rotation () measurements. Despite the increase in induced by Ta doping, the superfluid density is found to be extremely low, even lower than in undoped while the superconducting gap becomes nodeless, indicating a crossover from nodal to nodeless pairing driven by disorder. Modest hydrostatic pressure drives both the superfluid density and to their optimal values in the undoped compound. This demonstrates that disorder does not limit the optimal superconducting state. In contrast, disorder has a pronounced impact on the normal‐state properties, giving rise to giant field‐enhanced relaxation below the charge‐order temperature and a Curie–Weiss‐like Knight shift, indicative of local‐moment magnetism. Furthermore, unlike disorder‐free and Nb‐doped , ‐KVS exhibits no depth dependence of the normal‐state relaxation rate. Together, these findings reveal that disorder fundamentally alters the interplay between orbital and local‐moment magnetism, with distinct impacts on superconductivity and normal‐state magnetism.