Anisotropy of the upper critical field and critical current in single crystalMgB2

L. Lyard, P. Samuely, P. Szabo, T. Klein, C. Marcenat, L. Paulius, K. H. P. Kim, C. U. Jung, H.-S. Lee, B. Kang, S. Choi, S.-I. Lee (+6 others)
2002 Physical Review B (Condensed Matter)  
We report on specific heat, high magnetic field transport and ac-susceptibility measurements on magnesium diboride single crystals. The upper critical field H_c2 for magnetic fields perpendicular and parallel to the Mg and B planes is presented for the first time in the entire temperature range. A very different temperature dependence has been observed in the two directions which yields to a temperature dependent anisotropy with Γ∼ 5 at low temperatures and about 2 near T_c. A peak effect is
more » ... erved in susceptibility measurements for H ∼ 2 T parallel to the c-axis and the critical current density presnts a sharp maximum for H parallel to the ab-plane.
doi:10.1103/physrevb.66.180502 fatcat:cqamxsgy55fgvhhlls24dprgja