Acta Physica Polonica B

Vol. 34, No. 2, February 2003, page 549


Anisotropic Critical Fields of MgB2 Single Crystals

T. Dahm, A.I. Posazhennikova, K. Maki

The recently discovered superconductivity in MgB2 has created the world sensation. In spite of the relatively high superconducting transition temperature Tc=39 K, the superconductivity is understood in terms of rare two gap superconductor with energy gaps attached to the \sigma and \pi -band. However, this simple model cannot describe the temperature dependent anisotropy in Hc2 or the temperature dependence of the anisotropic magnetic penetration depth. Here we propose a model with two anisotropic energy gaps with different shapes. Indeed the present model describes a number of peculiarities of MgB2 which have been revealed only recently through single crystal MgB2.

PACS numbers: 74.20.Rp, 74.25.Bt, 74.70.Ad


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