2002/01/31 by A. V. Sologubenko, J. Jun, S. M. Kazakov +4 · 6 citations
Materials Science · Physics and Astronomy · #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #Thermal Expansion and Ionic Conductivity #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.66.014504
published as Phys. Rev. B 66, 014504 (2002) · 9 pages,7 figures
openalex publication_date 2002/06/21 · arxiv created 2002/06/25 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The ab-plane thermal conductivity \ensuremathκ of single-crystalline hexagonal MgB2 has been measured as a function of magnetic field H with orientations both parallel and perpendicular to the c axis and at temperatures between 0.5 and 300 K. In the mixed state, \ensuremathκ(H) measured at constant temperatures reveals features that are not typical for common type-II superconductors. The observed behavior may be associated with the field-induced reduction of two superconducting energy gaps, significantly different in magnitude. A nonlinear temperature dependence of the electronic thermal conductivity is observed in the field-induced normal state at low temperatures. This behavior is at variance with the law of Wiedemann and Franz, and suggests an unexpected instability of the electronic subsystem in the normal state at T\ensuremath≈1K.