μSR study of intermediate heavy fermion system CeRuSi₂

Abstract

ZF, LF and TF μSR measurements have been carried out with a polycrystalline CeRuSi₂ sample. ZF data show a sharp increase of the muon relaxation rate below the temperature T=12 K (0.42 μ s^-1 at T=4.2 K) justifying the phase transition to the magnetically ordered state. The results of LF measurements at T=4.2 K show that the magnetic fields on the muon B_μ, produced by the cerium magnetic moments, are mainly static – external longitudinal field of 150 Oe practically recovers the muon spin polarization. In the paramagnetic phase the polarization decay has an exponential form at all measured temperatures 20 K < T < K, though LF experiment at T=20 K clearly shows a significant static contribution (\sim 75%). This situation is discussed in frames of double relaxation model. The ferromagnetic type of magnetic ordering was proved by hysteresis behavior of (B–H) observed in TF‐experiment.