Muon spin relaxation in a spin glass CuMn observed in finite longitudinal magnetic fields

Abstract Muon spin depolarization in a spin glass Cu Mn (1.1 at .%, T g = 10.8 K) has been observed in longitudinal external magnetic fields H L = 0–640 Oe. The depolarization rate did not depend on H L at T > T g , reflecting a fast dynamical fluctuation of Mn moments. In contrast, a remarkable field dependence was observed below T g . Static and dynamical local fields on μ + from Mn moments were found to coexist at T ∼ 0.9 T g . The results suggested a rapid change of spin dynamics around T g .