Unconventional superconductivity and magnetism in CePt3Si1-xGex

Abstract CePt 3 Si is a novel ternary compound exhibiting antiferromagnetic order at T N ≈ 2.2 K and superconductivity (SC) at T c ≈ 0.75 K . Large values of H c 2 ′ ≈ - 8.5 T / K and H c 2 ( 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 μ SR measurements evidence coexistence of SC and long-range magnetic order on a microscopic scale. Moreover, CePt 3 Si is the first heavy fermion SC without an inversion symmetry. This gives rise to a novel type of NMR relaxation rate 1 / T 1 which is very unique and never reported before for other heavy fermion superconductors. Studies of Si/Ge substitution allow us to establish a phase diagram.