Mixed state properties of iron based Fe(Se,Te) superconductor fabricated by Bridgman and by self-flux methods

Abstract

The superconducting and transport properties of iron based Fe(Se,Te) superconductors fabricated by means of Bridgman (B) and Self-flux (S) methods have been compared using dc Magnetization (M) measurements as a function of temperature (T) and magnetic field (H). The M(T) measurements performed in Zero Field Cooling-Field Cooling conditions show higher critical temperature Tc and a lower spurious magnetic background signal for the sample (B) rather than the (S) one. By considering the superconducting M(H) hysteresis loops, the sample (B) shows a stronger superconducting signal together with the presence of a peak effect. The field and temperature dependence of the critical current densities Jc are extracted from the superconducting hysteresis loops M(H) within the Bean critical state model, and the high ratio between the JcB and the JcS, relative to the two typologies of samples, together with the comparison between their upper critical field Hc2, points out that the Bridgman method is most attractive for exploiting superconducting and transport properties in view of applications.