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arXiv · 1303.0352

Two-band effect on the vortex dynamics and critical current density in an anisotropic MgB$_2$ thin film

Jeehoon Kim·N. Haberkorn·E. Nazaretski·R. de Paula·X. X. Xi·T. Tajima·R. Movshovich·L. Civale
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Abstract

We report the influence of intrinsic superconducting parameters on the vortex dynamics and the critical current densities of a MgB$_2$ thin film. The small magnetic penetration depth of \lambda = 50 nm at T=4 K is related to a clean \pi-band, and transport and magnetization data show an upper critical field similar to those reported in clean single crystals. We find a high self-field critical current density Jc, which is strongly reduced with applied magnetic field, and attribute this to suppression of the superconductivity in the \pi-band. The temperature dependence of the creep rate S(T) at low magnetic field can be explained by a simple Anderson-Kim mechanism. The system shows high pinning energies at low field that are strongly suppressed by high field, which is consistent with a two-band contribution.

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Jeehoon Kim, N. Haberkorn, E. Nazaretski, R. de Paula, X. X. Xi, T. Tajima, R. Movshovich, L. Civale. 2013-03-02. Two-band effect on the vortex dynamics and critical current density in an anisotropic MgB$_2$ thin film. https://arxiv.org/abs/1303.0352

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