英文摘要
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A broad superconducting transition with bulk Tc of 14 K and a diamagnetic onset as high as 20 K was observed for the met&able, as-melted ThPd2B2C sample from magnetic studies. Low temperature specific heat data yield a bulk Tc of 14 K, an electronic-term coefficient 7 of 12 mJ/molK^2 and a Debye temperature өD of 320 K. The systematic variation of Tc for the nonmagnetic quaternary borocarbides RT2B2C (R = Sc, Y, Lu, La, Th; T = Ni. Pd, Pt) is correlated with the electronic-term coefficient 7 and the transition metal T-T nearest-neighbor in-plane distance. The variation of the transitional metal 3d/4d/5d-dominated conduction band and thus the Fermi-level density of states N(EF) is believed to be the determining factors for Tc variation of these borocarbides.
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