2001/04/30 by H. D. Yang, J. -Y. Lin, J.‐Y. Lin +10 · 3 citations
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.87.167003
7 pages, 5 figures; revised text and figures; references updated, Phys. Rev. Lett., in press
arxiv created 2001/09/21 · openalex publication_date 2001/09/26 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We have measured the low-temperature specific heat C(T) for polycrystalline MgB2 prepared by high pressure synthesis. C(T) below 10 K vanishes exponentially, which unambiguously indicates a fully opened superconducting energy gap. However, this gap is found to be too small to account for Tc of MgB2. Together with the small specific heat jump \ensuremathΔC/\ensuremathγnTc\phantom\rule0ex0ex=\phantom\rule0ex0ex1.09, scenarios such as anisotropic s-wave or multicomponent order parameter are called for. The magnetic field dependence of \ensuremathγ(H) is neither linear for a fully gapped s-wave superconductor nor H1/2 for nodal order parameter. It seems that this intriguing behavior of \ensuremathγ(H) is associated with the intrinsic electronic properties other than flux pinning.