Decoupling of muonium in high transverse magnetic fields

Depolarization of muonium due to superhyperfine interaction, which until now has severely impeded the study of muonium in solids, can be quenched in a high transverse magnetic field (1.2 T). We report the observation of muonium precession in single crystals of KCl, CaF2, GaP, and Al2O3. The high-field frequencies are of order 2 GHz and provide a direct and accurate (60 ppm) measure of the hyperfine interval. Several novel features of the muonium centers are observed. © 1984 The American Physical Society.