Reversible magnetization of MgB2 single crystals with a two-gap nature -: art. no. 144514

We present reversible magnetization measurements on MgB2 single crystals in magnetic fields up to 2.5 T applied parallel to the crystal's c axis. This magnetization is analyzed in terms of the Hao-Clem model, and various superconducting parameters, such as the critical fields [H-c(0) and H-c2(0)], the characteristic lengths [xi(0) and lambda(0)], and the Ginzburg-Landau parameter, kappa are derived. The temperature dependence of the magnetic penetration depth lambda(T), obtained from the Hao-Clem analysis, could not be explained by theories assuming a single gap. Our data are well described by using a two-gap model.