Anisotropic superconducting properties of FeSe_0.5Te_0.5 single crystals

We investigated the anisotropic electrical transport and magnetic properties of FeSe_0.5Te_0.5 single crystals grown by the self-flux method. The in-plane resistivity shows a metallic-like temperature dependence, while the out-of-plane resistivity shows a broad hump with a maximum at around 64 K. The magnetization loops for H/\!/c-axis and H/\!/ab-plane are also different, for example, there is a typical second peak for H/\!/c-axis. The in-plane critical current density is larger than the out-of-plane one. The coherence length and penetration depth were estimated by the Ginzburg-Landau theory. The anisotropic parameter \gamma depends on the applied magnetic field and the temperature. The coupling of superconducting FeSe(Te) layers and the flux pinning mechanism relevant to anisotropy are also discussed.