A study was made of the upper critical field HC2 of 2-band superconductors by using the 2-band Ginzburg–Landau approach. The analytical formula of HC2 included anisotropy of the order parameter, and anisotropy of the effective mass was found. The parameters of the upper critical field in the ab-plane (HC2||ab) and c-axis (HC2||c) could be found by fitting experimental data. Finally, it was found that the ratio of upper critical field was temperature-dependent within the range of the experimental results.

HC2 of Anisotropic Two-Band Superconductors by Ginzburg–Landau Approach. P.Udomsamuthirun, A.Changjan, C.Kumvongsa, S.Yoksan: Physica C, 2006, 434[1], 62-6