OBSERVATION OF SUPERCONDUCTIVITY IN POLYCRYSTALLINE DYNI2B2C

One of the offshoots of the discovery of superconductivity (SC) in the Y-Ni-B-C system is the coexistence of SC and magnetism in RNi(2)B(2)C (R = Er, Ho, Tm). Here we report our observation of SC (T-c similar t o 6 K) and magnetic order (T-N similar to 11 K) in polycrystalline DyN i2B2C. This is one of a few systems where SC sets in with T-c<T-N. Fro m the known systematics of T-c and T-N in borocarbide systems, we expe ct YbNi2B2C to exhibit SC around 12 K. However, our resistivity measur ements in YbNi2B2C do not reveal SC down to 1.5 K.