2001/07/04 by R. A. Fisher, F. Bouquet, N. E. Phillips +2
Physics and Astronomy · #cond-mat.supr-con
published as "Studies of High Temperature Superconductors" Vol 38, Ed. A. V. Narlikar, Nova Science, NY · 10 pages in PDF format containing text plus figures in 1 unzipped file. Replacement was to make changes to the abstract
arxiv created 2001/07/04 · arxiv updated 2009/11/30
This paper reports specific-heat measurements on superconducting MgB2 in magnetic fields to 9 T. In zero magnetic field the data can be fitted to a two-gap model, which is a generalization of a semi-empirical model for strong-coupled, single-gap superconductors (the alpha-model), to within the precision of the data. Both gaps close at Tc, with one gap larger and one smaller than the BCS weak-coupling-limit. (The two gaps have a ratio ~ 4:1.) Each gap accounts for ~ 50% of the normal electron density of states. The parameters characterizing the fits agree well with those from recent spectroscopic measurements and theory. In magnetic fields the superconductong anomaly is broadened as expected for an anisotropic, randomly-oriented superconductor.