Novel Superconductivity and Magnetism in CePt₃Si

Abstract

CePt₃Si exhibits antiferromagnetic order at T _N ≈ 2.2 K and superconductivity (SC) at T _c ≈ 0.75 K. Large values of H′ _c2 ≈ −8.5 T/K and H _c2(0) ≈ 5 T indicate Cooper pairs formed out of heavy quasiparticles. The mass enhancement originates from Kondo interaction with a characteristic temperature T _K ≈ 8 K. NMR and μSR measurements evidence coexistence of SC and long-range magnetic order on a microscopic scale. Moreover, CePt₃Si is the first heavy-fermion SC without an inversion symmetry. This gives rise to a novel type of the NMR relaxation rate 1/T ₁ never reported before for other heavy-fermion superconductors. Studies of Si/Ge substitution allow us to establish a phase diagram.