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Specific heat of single crystal MgB_2: a two-band superconductor with two different anisotropies

F. Bouquet·Y. Wang·I. Sheikin·T. Plackowski·A. Junod·S. Lee·S. Tajima
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Abstract

Heat-capacity measurements of a 39 microgramm MgB_2 single crystal in fields up to 14 T and below 3 K allow the determination of the low-temperature linear term of the specific heat, its field dependence and its anisotropy. Our results are compatible with two-band superconductivity, the band carrying the small gap being isotropic, that carrying the large gap having an anisotropy of ~ 5. Three different upper critical fields are thus needed to describe the superconducting state of MgB2.

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F. Bouquet, Y. Wang, I. Sheikin, T. Plackowski, A. Junod, S. Lee, S. Tajima. 2002-10-31. Specific heat of single crystal MgB_2: a two-band superconductor with two different anisotropies. https://doi.org/10.1103/physrevlett.89.257001

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