NON-CENTROSYMMETRIC HEAVY FERMION SUPERCONDUCTIVITY IN CeCoGe3

Abstract

We measured the electrical resistivity under pressure for an antiferromagnet CeCoGe 3 without inversion symmetry in the tetragonal crystal structure. The Néel temperature T N1 = 21 K at ambient pressure decreases monotonically with increasing pressure, and becomes zero at about 5.5 GPa. Superconductivity appears above 4.3 GPa, with a superconduting transition temperature T sc = 0.72 K and a large upper critical field H c2 (0) = 7 T at 5.6 GPa. The large upper critical field H c2 (0)= 7 T exceeds the Pauli limitting field H p (≃ 1.86T sc )=1.3 T as in CePt 3 Si , CeRhSi 3 and CeIrSi 3. The large slope of H c2 at T sc , -dH c2 /dT = 18 T/K , at 5.6 GPa indicates the heavy-fermion superconductivity in CeCoGe 3.