Static magnetic ordering of CeCu 2.1Si 2 found by muon spin relaxation

Abstract

Zero- and longitudinal-field muon spin relaxation measurements on a poly-crystal sample of a heavy-fermion superconductor CeCu 2.1 Si 2 ( T c = 0.7 K) have revealed an onset of static magnetic ordering below T ∼ 0.8 K. The line shapes of the observed spectra in zero field indicate a wide distribution of static random local fields at muon sites, suggesting that the ordering is either spin glass or incommensurate spin-density-wave state. The observed width of the random local field at T = 0.05 K corresponds to a small averaged static moment of the order of 0.1μ B per formula unit.