Field dependence of the muon spin relaxation rate in MnSi.

0K[1]. In a mag-netic field, the magnetic structure transforms progres-sively from helical to conical to ferromagnetic, asshown in Fig. 1(a). Above 6.2 kG (at 4.2 K) the systembehaves like a ferromagnet having a relatively large highfield susceptibility [3]. In the paramagnetic state themagnetic susceptibility obeys a Curie-Weiss law up to400 K [4].This system has been extensively studied as a proto-type of itinerant weak ferromagnets which follow pre-dictions of the self-consistent renormalization (SCR)theory developed by Moriya, Kawabata, and co-workers[5]. The SCR theory overcomes shortcomings of earliermean field (Stoner-Slater) theory and random phase ap-proximation, and successfully explains the Curie-Weissbehavior of , the ordering temperature, and other prop-erties of the metallic ferro- and antiferromagnets, such asFe, Ni, and ZrZn