Zero-field (ZF), longitudinal field (LF), muon spin relaxation (μSR), and transverse field (TF) muon spin rotation (μSR) measurements have been carried out on a polycrystalline sample ${\mathrm{CeRuSi}}_2$. ZF data show a sharp increase in the muon relaxation rate below the temperature 12 K (0.42 μ${\mathrm{s}}^{\mathrm{-}1}$ at T=4.2 K), justifying the transition to the magnetically ordered state. From the LF measurements at T=4.2 K, we found that the magnetic fields on the muon, ${\mathrm{B}}_{\mathrm{\mu }}$, produced by the cerium magnetic moments are mainly static:mThe external longitudinal field of 150 G practically recovers muon spin polarization. In the paramagnetic phase the polarization has an exponential form in the whole range of temperatures 20 K${\mathrm{T}}_{\mathrm{C}}$=11.6 K. The width of the field distribution obtained in the TF experiment corresponds to the ordered moment (0.005–0.05)${\mathrm{\mu }}_{\mathrm{B}}$, depending on the assumed muon site.

• Received 18 April 1996

DOI:https://doi.org/10.1103/PhysRevB.55.12343