Field and angular dependence of the Sommerfeld coefficient in Al-doped MgB2 single crystals

Z. Pribulova , Thierry Klein (1) , Jacques Marcus (2) , C. Marcenat (3) , M. S. Park (4) , H.S. Lee (4) , H.G. Lee (4) , S.I. Lee (4)

1 NEEL - MagSup - Magnétisme et Supraconductivité
2 NEEL - AUTOCARAC - Automatisation & caractérisation
3 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
4 NVCRICS

The angular and field dependence of the Sommerfeld coefficient = lim Cel /T T→0 Cel being the electronic contribution to the specific heat has been measured in Al-doped MgB2 single crystals for x=0, x=0.1, and x 0.2 . We show that the decomposition previously introduced to describe H, where is the angle between the applied field and the c axis in pure samples Phys. Rev. Lett. 98, 137001 2007 is well adapted to doped samples: e.g., the contribution of the band to the specific heat is proportional to B/Bc2 whereas the contribution of the band is isotropic but highly nonlinear in field. We hence present the evolution of the coherence lengths of the two bands and corresponding Fermi velocities with doping.

Mots clés: supraconductivité

Domaines: Supraconductivité [cond-mat.supr-con]

Z. Pribulova, Thierry Klein, Jacques Marcus, C. Marcenat, M. S. Park, et al.. Field and angular dependence of the Sommerfeld coefficient in Al-doped MgB2 single crystals. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007, 76, pp.180502(R). ⟨10.1103/PhysRevB.76.180502⟩. ⟨hal-00957174⟩