ZERO-FIELD AND LOW-FIELD SPIN RELAXATION STUDIED BY POSITIVE MUONS

Zero- and low-field spin-relaxation functions have been studied for the first time by using positive muons, and results are compared with the stochastic theory of low-field relaxation formulated by Kubo and Toyabe. The dipolar broadening of the zero-field relaxation has been studied in detail. In ZrH2, the zero-field relaxation function of μ+ has been found to decay (5)1/2 times faster than the high-field relaxation function, which is explained in terms of the contribution of the nonsecular part of the dipolar interaction. Advantages of the zero-field method over the conventional muon-spin rotation method in practical applications, especially for studies of the μ+ diffusion/trapping, are discussed. © 1979 The American Physical Society.