Mixed state properties of superconducting MgB2 single crystals
  We report on measurements of the magnetic moment in superconducting MgB2 single crystals. We find \mu_0H_{c2}^c(0) = 3.2 T, \mu_0H_{c2}^{ab}(0) = 14.5 T, \gamma = 4.6, \mu_0H_c(0) = 0.28 T, and \kappa(T_c) = 4.7. The standard Ginzburg-Landau and London model relations lead to a consistent data set and indicate that MgB2 is a clean limit superconductor of intermediate coupling strength with very pronounced anisotropy effects. 
M. Zehetmayer, M. Eisterer, H. W. Weber, J. Jun, S. M. Kazakov, J.   Karpinski, A. Wisniewski