Borocarbide and silicocarbide intermetallic Y2NixB82xC2 ~x51, 2, 3, 5!, YNiCuB2C, and YNixCu22xSi2C ~x50, 2! were prepared and their superconductivity was studied. The results indicated that with the change of the ratio of Ni to B in Y2NixB82xC2 , secondary phases were introduced into YNi2B2C phase. A Tc of 15.0 K was observed for the compounds x52, 3, and 5, which originated from the major phase YNi2B2C in these samples. Partial substitution of Ni by Cu reduced the Tc to 11.0 K for YNiCuB2C. For Si substitution system, no bulk superconductivity was found in YNi2Si2C and YCu2Si2C. But a minor superconducting phase ~Tc;4 K! with a volume fraction of the order of near 1% was observed in them. It was noticed that for the temperature dependent magnetization of superconducting compounds containing Ni, a significant difference between zero-field cooling and field cooling curves before Tc was always observed, which was tentatively attributed to Ni-containing impurity. © 1996 American Institute of Physics.
Zhao, Wei; Tang, Jinke; Lee, Young-sook; and O’Connor, Charles J. (1996). "Synthesis and superconductivity of intermetallic compounds Y2Ni x B8−x C2, YNi x Cu2−x B2C, and YNi x Cu2−x Si2C." JOURNAL OF APPLIED PHYSICS 79.8, 5870-5872.