NMR and μSR investigation of spin dynamics in {Mo₇₂Fe ₃₀} molecular clusters

We present μ⁺SR and proton NMR data on the molecular cluster {Mo₇₂Fe₃₀} in its standard form (std-Fe30) and in its layered form (lay-Fe30) where the quasi-spherical molecules form a grid. μ⁺SR experiments on std-Fe30 as a function of the magnetic field at T≈30mK showed that the muon asymmetry has two components, corresponding to different muon sites, near and far from the magnetic ions. At the level crossing we observed an onset of local fields but no anomaly in the relaxation rate. Also a small effect of the spin topology was observed by means of ¹H NMR.