μ± precession studies of magnetic materials

The muon has recently begun to be used to study solid state. A review of this work to date and a description of current and proposed experiments will be made. The use of this proble is analogous to perturbed angular correlation with several special advantages: the muon is produced ?100% polarized, the decay μ→e+ν+ν produces highly anisotropic (1 + 1/3 cos ϑ) energetic charged leptons (up to 50 MeV), the lifetime of the muon (2.2 μ sec) is sufficiently long for easy timing and short enough for high count rates. The μ+ behaves as a light hydrogen ion and is thus the simplest impurity problem. Consequently the use of muons should not only yield fundamental solid state information, but also contribute to the understanding of radioactive ion implantation, particularly in the case of ferromagnetic samples.