Bulk superconductivity at an elevated temperature (T c ≊12 K) in a nickel containing alloy system Y-Ni-B-C

摘要: We report here our discovery of bulk superconductivity at rather high ${\mathit{T}}_{\mathit{c}}$ in samples having nominal compositions ${\mathrm{YNi}}_{4}$${\mathrm{BO}}_{0.2}$ (${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}12.5 K) and ${\mathrm{YNi}}_{2}$${\mathrm{B}}_{3}$${\mathrm{O}}_{0.2}$ (${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}13.5 K). While ${\mathrm{YNi}}_{4}$${\mathrm{BC}}_{0.2}$ seems to be a single phase material, ${\mathrm{YNi}}_{2}$${\mathrm{B}}_{3}$${\mathrm{C}}_{0.2}$ is multiphase system. Our experimental results show that the two materials are distinct superconductors. Discovery these significance since not only their (g10 but they also have nickel large proportions. No nickel-based ternary superconductor was previously known.