Superconductivity in MgCNi$_{3}$.Tunneling and heat capacity on single crystals

ORAL

Abstract

MgCNi$_{3}$ reveals superconductivity despite a large molar volume of Ni atoms. The origin of superconductivity in this material has not yet been clarified. There is a lot of discrepancy in experimental results and physical interpretation where even unconventional pairing or a two-band model have been proposed for the system, but these suggestions are based on measurements on polycrystalline samples. Here we present the point-contact tunneling spectroscopy and ac-calorimetry measurements on single crystals of very good quality. Measurements have been performed in the temperature range from 0.7 K and in magnetic fields up to 8 T. The temperature dependence of the energy gap of the system is presented and compared to the BCS model.

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Authors

  • Peter Samuely

    Centre of Low Temperature Physics at the IEP Slovak Academy of Sciences and P.J. \v{S}af\'arik University, Watsonova 47, 040 01 Ko\v{s}ice, Slovakia

  • Zuzana Pribulova

    Centre of Low Temperature Physics at the IEP Slovak Academy of Sciences and P.J. \v{S}af\'arik University, Watsonova 47, 040 01 Ko\v{s}ice, Slovakia

  • Jozef Kacmarcik

    Centre of Low Temperature Physics at the IEP Slovak Academy of Sciences and P.J. \v{S}af\'arik University, Watsonova 47, 040 01 Ko\v{s}ice, Slovakia

  • Pavol Szabo

    Centre of Low Temperature Physics at the IEP Slovak Academy of Sciences and P.J. \v{S}af\'arik University, Watsonova 47, 040 01 Ko\v{s}ice, Slovakia

  • Christophe Marcenat

    CEA-Grenoble, D\'epartement de Recherche Fondamental sur la Mati\`ere Condens\'ee, F-38054 Grenoble Cedex 9, France

  • Thierry Klein

    Institut N\'eel, CNRS, BP166 38042 Grenoble Cedex 9, France

  • D.-J. Jang

    NVCRICS and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea

  • H.-G. Lee

    NVCRICS and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea

  • H.-S. Lee

    NVCRICS and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea

  • S.-I. Lee

    NVCRICS and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea, Pohang University of Science and Technology, Pohong U, Korea, Phys. Dept., Pohang U., Korea