Coexisting static magnetic order and superconductivity inCeCu2.1Si2found by muon spin relaxation

Abstract

Zero- and longitudinal-field muon-spin-relaxation measurements on a heavy-fermion system ${\mathrm{CeCu}}_{2.1}$ ${\mathrm{Si}}_2$ have revealed an onset of static magnetic ordering below $T_M$∼0.8 K, which coexists with superconductivity below $T_C$=0.7 K. The line shapes of the observed muon spin depolarization functions suggest an ordering in either the spin-glass or incommensurate spin-density-wave states, with a small averaged static moment of the order of 0.1${\mu }_B$ per formula unit at T→0.