The flux pinning force and vortex phase diagram of single crystal

The flux pinning force density ( F p ) of the single crystalline FeTe0.60Se0.40 superconductor has been calculated from magnetization measurements. The normalized F p versus h ( = H / H i r r ) curves are scaled using the Dew–Hughes’s formula f ( h ) ∼ h p ( 1 − h ) q to underline the pinning mechanism in the compound. The obtained values of pinning parameters ‘ p ’ and ‘ q ’ indicate point core pinning of the normal centers along with the presence of the surface pinning. The vortex phase diagram has also been drawn for the first time for FeTe0.60Se0.40, which has very high values of critical current density J c ∼ 1 × 10 5 A/cm 2 at T = 2 K and, the upper critical field H c 2 ( 0 ) ∼ 65 T , with a reasonably high transition temperature T c = 14.5 K .