Magnetic and superconducting behaviour of Er1−Tb Ni2B2C1.02 and Er1−Tb Ni2B2C0.98

Abstract We looked for re-entrant superconductivity in zero field in the Er 1− x Tb x Ni 2 B 2 C y systems ( y =0.98; x =0.1, 0.12, 0.13, 0.16, 0.20, 0.25, 0.30 and y =1.02; x =0.0, 0.05, 0.13–0.20, 0.25, 0.30, 0.35, 0.40) because substitution of Er by Tb (larger de Gennes factor) magnetically depresses T c and the critical field H c2 . However, none of our samples exhibited such a behaviour. An Abrikosov–Gorkov law is followed by T c ( x ) in the y =1.02 system while T c ( x ) of the y =0.98 system breaks this law.