## Growth, Characterization, Vortex Pinning and Vortex Flow Properties of Single Crystals of Iron Chalcogenide Superconductor FeCr$_{0.02}$Se    [PDF]

Anil K. Yadav, Ajay D. Thakur, C. V. Tomy
We report the growth and characterization of single crystals of iron chalcogenide superconductor FeCr$_{0.02}$Se. There is an enhancement of the superconducting transition temperature (T$_c$) as compared to the single crystal of the parent compound Fe$_{1+x}$Se by about 25%. The superconducting parameters such as the critical fields, coherence length, penetration depth and the Ginzburg-Landau parameter have been estimated for these single crystals and compared with related Fe-based superconductors. Analysis of the critical current data suggests a $\delta l$ pinning mechanism in this material. Thermally activated transport across the superconducting transition in the presence of external magnetic field suggest a crossover from a single vortex pinning regime at low fields to a collective flux creep regime at higher magnetic fields. Nature of charge carriers in the normal state estimated from Hall effect and thermal transport measurements could provide crucial information on the mechanism of superconductivity in Fe-based materials.
View original: http://arxiv.org/abs/1212.0814