Vortex-glass phase transition and enhanced flux pinning in C4+-irradiated BaFe1.9Ni0.1As2 superconducting single crystals

We report the effects of C4+-irradiation on the superconducting properties of BaFe1.9Ni0.1As2 single crystal. The BaFe1.9Ni0.1As2 single crystal before and after C4+-irradiation was characterized by magnetic, magneto-transport and magneto-optical techniques over a wide range of magnetic fields (0–13 T) and temperatures (2–200 K). We demonstrate that the C4+-irradiation significantly enhances the in-field critical current density (by a factor of up to 1.5 at 5 K) and induces enhanced flux jumping at 2 K, with only a small degradation (by 0.5 K) of the critical temperature, Tc. The vortex phase diagram describing the evolution of the vortex-glass transition temperature with magnetic field and the upper critical field has been resolved for the C4+-irradiated sample. For temperatures below Tc, the resistivity curves and the pinning potential were found to show good scaling, using a modified model for vortex-liquid resistivity. The vortex state is three dimensional at temperatures lower than a characteristic temperature. Good agreement between the thermally activated flux flow model, which is usually employed to account for the resistivity in the vortex-liquid region, and the modified vortex-liquid model, has been observed. © 2013 IOP Publishing

Keywords

Phase transformations, Vortex theory, Magnetic flux, Superconductivity, Crystals, Irradiation

Citation

Shahbazi, M., Wang, X. L., Ghorbani, S. R., Ionescu, M., Shcherbakova, O. V., Wells, F. S., Pan, A. V., & Choi, K. Y. (2013). Vortex-glass phase transition and enhanced flux pinning in C4+-irradiated BaFe1.9Ni0.1As2 superconducting single crystals. Superconductor Science and Technology, 26(9), 095014. doi:10.1088/0953-2048/26/9/095014