NEW SUPERCONDUCTING AND MAGNETIC R-T-B-C SYSTEMS (R=RARE EARTH T=NI, PD)

Our discovery of superconductivity in Y-Ni-B-C system (T-c similar to 12 K) has opened up a new field in superconductivity and magnetism in intermetallics. A brief description of the discovery of these new borocarbide materials is given. We have synthesised NdNi2B2C and GdNi2B2C for the first time and our measurements show that NdNi2B2C (T-m similar to 5 K) and GdNi2B2C (T-m similar to 19 K) undergo magnetic ordering. CeNi2B2C does not exhibit magnetic ordering down to 4.2 K; the magnitude of its magnetic susceptibility is consistent with Ce ions in mixed valence state. We comment on the magnetic properties of the two superconducting materials ErNi2B2C and LuNi2B2C.