Precession experiments of positive muons in ferromagnetic materials

A review of mu /sup +/ precession experiments on ferromagnetic samples is made. In these experiments, the temperature and applied magnetic field were varied and the precession frequency, initial polarization, and depolarization rate were measured. Possible interpretations of the results are presented. Likely sources of the field felt at the muon are the contact hyperfine field from conduction electrons which shield the mu /sup +/ and the dipole field sum for the case of Fe. Depolarization may in part be due to field inhomogeneities, defects, and single magnon interactions. Initial polarization may reflect domain alignment. Future experiments are discussed. (23 refs).