Magnetic and superconducting phase diagram of noncentrosymmetric CeRhSi₃

The noncentrosymmetric heavy fermion superconductor CeRhSi₃ exhibits an extremely large superconducting upper critical field B_c2 for the magnetic field along the c axis. This remarkable feature is ascribed to the noncentrosymmetric (Rashba-type) crystal structure which can avoid the paramagnetic pair-breaking effect. The pressure dependence of the B _c2(T) curve, however, is very complicated and remains as an unresolved issue. Recently, we found a bend in the B_c2(T) curve which emerges at a pressure where the antiferromagnetic order disappears. Furthermore, an anomaly in the electrical resistivity in the normal state emerges above the magnetic field of the bend point. The obtained magnetic and superconducting phase diagram thus appears to have complicated structure especially in the vicinity of the pressure where the antiferromagnetic order vanishes.