Pressure-induced enhancement of the superconducting properties of single-crystalline FeTe0.5Se0.5

The pressure dependence, up to 11.3 kbar, of basic parameters of the superconducting state, such as the critical temperature (T-c), the lower and the upper critical fields, the coherence length, the penetration depth, and their anisotropy, was determined from magnetic measurements performed for two single-crystalline samples of FeTe0.5Se0.5. We have found pressure-induced enhancement of all of the superconducting state properties, which entails a growth of the density of superconducting carriers. However, we noticed a more pronounced increase in the superconducting carrier density under pressure than that in the critical temperature which may indicate an appearance of a mechanism limiting the increase of T-c with pressure. We have observed that the critical current density increases under pressure by at least one order of magnitude.