Muon spin relaxation in isotropic ferromagnets in the vicinity of critical paramagnetic Tc

A theoretical description of muon spin relaxation in cubic ferromagnetics (FM) in the paramagnetic Tc vicinity is given. General expressions for transverse and longitudinal λ relaxation rates as the reduced temperature τ and magnetic field H functions are derived. On this base temperature dependences λ in Fe and Ni are discussed. Peculiarities of temperature behaviour Δ ωμ near Tc (Δωμ-muon precession frequency shift) are considered. Comparison of muon data to the results obtained in Fe and Ni using disturbed angular correlation method is conducted. λparallel dependence on H field is theoretically investigated and possibility of experimental study of spin diffusion phenomenon near Tc is indicated