Superconductivity at T-c similar to 14 K in single-crystalline FeTe0.61Se0.39

Single-crystalline FeTe0.61Se0.39 with a sharp superconducting transition at T-c similar to 14 K is synthesized via slow furnace cooling followed by low-temperature annealing. The effect of annealing on the chemical and superconducting inhomogeneities is carefully characterized. We also report resistivity, magnetization, and magneto-optical images of this crystal. Based on the Bean model, critical current density is estimated to exceed 1x10(5) A/cm(2) below 5 K under zero field. Weak fish-tail effect is identified at lower temperatures.