Abstract
Superconducting quantum interference device dc magnetic susceptibility, ac magnetic susceptibility, ac electrical resistivity, and specific-heat measurements on bulk and powder samples of ThPt 2 B 2 C shows a bulk superconducting transition T c of 7 K with a transition width of 6.6-7.4 K. The low-temperature normal-state specific-heat data yield an electronic-term coefficient γ of 8.5 mJ/mol K 2 , a Debye temperature θ D of 330 K, and a bulk superconducting specific-heat jump ΔC at a T c of 1.53 γT c Contrary to the smooth variation of T c with the T-T in-plane distance for the nonmagnetic RT 2 B 2 C systems (R = Y Th, La; T = Ni, Pd), an anomalous T c variation with the Pt-Pt in-plane distance d(Pt-Pt) was observed for the nonmagnetic RPt 2 B 2 C system (R = Y, Th, La). This anomalous T c -d(Pt-Pt) relationship, along with the specific-heat γ value and normal-state Pauli paramagnetic susceptibility of lower-T c ThPt 2 B 2 C, suggests the importance of the Pt(5d)-dominated conduction band.