Superconductivity in Ba(TM,Si)2 (TM = Pd, Pt, Cu, Ag, and Au) with the AlB2-Type Structure

概要

論文の詳細を見る
We succeeded in synthesizing BaTMxSi2-x (TM = Pd, Pt, Cu, Ag, and Au) superconductors with the AlB2-type structure and performed detailed thermodynamic measurements of the superconducting state in BaTMxSi2-x to determine the superconducting parameters [H_{\text{c1}} (0), H_{\text{c2}}(0), \lambda (0), \xi (0), and \kappa_{\text{GL}}] using Ginzburg--Landau relations. The observed parameters indicated that BaTMxSi2-x can be categorized into a conventional type-II superconductor. The AlB2-type structure appears at x between 0.2 and 0.8, and the lattice parameters systematically changed with x. The superconductivity was observed at a TM concentration x = 0.2{\mbox{--}}0.6. T_{\text{c}} was almost constant between x = 0.2 and 0.3 and observed to decrease with increasing TM concentration (0.3 \leq x \leq 0.6). The specific heat data indicated that the superconductivity in BaTMxSi2-x exists in a weak coupling regime in the BCS theory. Moreover, we discussed the role of the TM element in BaTMxSi2-x using the observed data.
2012-11-15