Specific heat of the 38-K superconductor MgB₂ in the normal and superconducting state: bulk evidence for a double gap

2001/06/20 by Alain Junod, Yuxing Wang, Frederic Bouquet +1
Physics and Astronomy · #cond-mat.supr-con

paper · pdf

published as Studies of High Temperature Superconductors Ed. A.V. Narlikar, Nova Science Publishers, Commack, N.Y. 38 (2002) 179 · 27 pages, 11 figures, chapter for "Studies of High Temperature Superconductors Vol. 38", pdf format

arxiv created 2001/06/20 · arxiv updated 2009/11/30

Abstract

The specific heat of two polycrystalline samples of MgB₂ is presented and analyzed (2 - 300 K, 0 - 16 T), together with magnetic properties. The main characteristics are a low density of states at the Fermi level, high phonon frequencies, and an anomalous temperature- and field- dependence of the specific heat at T < T_c. A two-gap model with a gap ratio of 3:1 fits the specific heat in zero field. The smaller gap is washed out by a field of 0.5 T.

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