Time-Reversal Symmetry-Breaking Superconductivity in the Filled-Skutterudite(Current Topics)

Abstract

The filled-skutterudite PrO_S4Sb₁₂ has been attracting much attention because of the fact this is the only Pr-based heavy-fermion superconductor. Our muon spin relaxation measurements have revealed spontaneous appearance of static internal magnetic fields below the superconducting transition temperature. This observation provides unambiguous evidence for "the breaking of time-reversal symmetry" in the superconducting state.