2024/10/31 by R. Kadono, T. Ito, Kadono, Ryosuke +1 · 1 citation
Engineering · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Muon and positron interactions and applications #Neutrino Physics Research #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.2410.23575
openalex publication_date 2024/10/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We extend the previously published model that distinguishes between the diffusive motion of diamagnetic muons and the dynamics of ions around the muon in matter, and propose a generalized model for \sl paramagnetic muons (Mu0s, bound states of a muon and an unpaired electron) observed in non-metallic host materials. The new model distinguishes among the independent motion of unpaired electron associated with Mu0, the self-diffusive motion of Mu0 as single atomic entity, and that of the ions surrounding Mu0, where the muon spin relaxation is induced by dynamical fluctuations of the hyperfine (HF) field exerted from the unpaired electron (e.g., due to spin/charge exchange reaction) and/or that of the nuclear hyperfine (NHF) interactions between the unpaired electron and the surrounding ions. We have applied this model to the muonated radicals (Mu0s in a polaron state) in conducting polymers, and examined the validity of the interpretations claimed in the earlier literature that the spin relaxation is induced by quasi-one dimensional motion of the unpaired electron. The result suggests that experimental support for such a claim is still inadequate and needs to be reexamined, including the possibility of other origins for the fluctuations. It is expected that our model will prove a useful guide for μSR studies of various local dynamics involving paramagnetic muon states.