Quaternary borocarbide superconductors

Abstract

Discovery of superconductivity at a relatively high superconducting transition temperature in a nickel containing borocarbide system Y-Ni-B-C has led to a new field, namely quaternary borocarbide superconductors. The borocarbide superconductors have the highest T _c among all of the known intermetallic non-oxide superconductors. The RENi₂B₂C compounds containing magnetic rare earth ions (RE=Dy, Ho, Er or Tm) exhibit coexistence of superconductivity and antiferromagnetic ordering, with the highest coexistence temperature, and all combinations of T _c, and T _N, namely T _c > T _N, T _c < T _N (in which case superconductivity sets in a magnetically ordered lattice) and T _c ≈ T _N. We present here a brief review of some of the novel features of the borocarbide superconductors and suggest further experiments.