Disordered local moment , spin fluctuations

As just described, the field distribution at the muon site in a frozen, disordered (non-dilute moment) magnetic state is often not measured, because large-asymmetry muon signals are only seen at higher temperatures, where the spins are not fully frozen, and the dynamics partially decouples the muon from the large internal fields. Interpretation of the muon relaxation in terms of the behavior of the moment system generally requires a model of both the distribution of local fields caused by the moments, and the spectrum of moment fluctuations. With no detailed information on the field distribution from the static (low-temperature) limit, there can be considerable ambiguity in interpretation. 

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