Anisotropy of the upper critical field and critical current in single crystal MgB2

L. Lyard (1, 2) , P. Samuely (3, 4) , P. Szabo (4) , Thierry Klein (1) , C. Marcenat (2) , L. Paulius (2) , K.H.P. Kim (5) , C.U. Jung (5) , H.-S. Lee (5) , B. Kang (5) , S. Choi (5) , S.-I. Lee (5) , J. Marcus (1) , S. Blanchard (1) , A.G.M. Jansen (6) , U. Welp (7) , G. Karapetrov (7) , W.K. Kwok (7)

1 LEPES - Laboratoire d'Etudes des Propriétés Electroniques des Solides
2 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
3 University J.Fourier
4 CLTP IEP - Centre of Low Temperature Physics
5 NVCRICS
6 LNCMI-G - Laboratoire national des champs magnétiques intenses - Grenoble
7 MSD - Material Science Division [ANL]

We report on specific-heat, high-magnetic-field transport, and ac-susceptibility measurements on MgB2 single crystals. The upper critical field for magnetic fields perpendicular and parallel to the basal planes is presented in the entire temperature range. A very different temperature dependence has been observed in the two directions, which yields a temperature-dependent anisotropy with G;5 at low temperatures and ;2 near Tc . A peak effect is observed for m0H;2 T parallel to the c axis, and the critical current density presents a sharp maximum for H parallel to the ab plane.

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

L. Lyard, P. Samuely, P. Szabo, Thierry Klein, C. Marcenat, et al.. Anisotropy of the upper critical field and critical current in single crystal MgB2. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2002, 66, pp.180502(R). ⟨10.1103/PhysRevB.66.180502⟩. ⟨hal-00957733⟩