The flux pinning force and vortex phase diagram of single crystal

Abstract

The flux pinning force density (

The flux pinning mechanism, and electrical and magnetic anisotropy in Fe1.04Te0.6Se0.4 superconducting single crystal

“…2) is obtained with an f(h) dependence given by h 1.35 (1 À h) 19 possibly due to excess iron concentration in this compound. The value of p/(p þ q) % 0.3 agrees well with the peak positions of these compounds in the f versus h plot, and it is in good agreement with the reported value of h max % 0.28 for FeTe 0.6 Se 0.4 single crystal.…”

“…19 In this work, the vortex pinning mechanisms, pinning potential, and anisotropy of Fe 1.04 Te 0.6 Se 0.4 single crystal have been studied systematically by magnetic and transport measurements at different temperatures.…”

“…This value is slightly higher than the reported value (1 Â 10 9 A/m 2 at T ¼ 1.8 K and low field) in a FeTe 0.6 Se 0.4 single crystal. 19,22 It is likely that this is due to the enhanced iron concentration in Fe 1.04 Te 0.6 Te 0.4 single crystal, which introduces more defects into the crystal structure, and consequently, higher pinning potential into the system.…”

Magnetization hysteresis and time decay measurements in FeSe0.50Te0.50: Evidence for fluctuation in mean free path induced pinning

“…In our case, h max ≈ 0.36, implying that point pins alone can not rationalize the observed scenario. In the case of BaFe [15,28,29] used for the estimation of h must therefore be dealt with care (more so because H irr and H c2…”

Effects of Iodine Annealing on Fe1+yTe0.6Se0.4

“…Figure 3(c) summarizes the evolution of T c and the self-field J c (2 K) with the molar ratio of iodine. T c reaches the highest value of 14.5 K when annealing in 6.7% iodine and J c is up to 5×10 5 A/cm 2 after annealing in 5.6% iodine under a self-field at 2 K, which is larger than those reported for Fe(Te,Se) [10,[21][22][23][24][25][26] and similar to the highest reported value for oxygen-annealed Fe 1+y Te 0.6 Se 0.4 [13,27]. It has been proved that such a large J c cannot be obtained from the superconductivity only near the surface [13], which indicates that the sample maintaining such a large J c obtained in our experiment must be a bulk superconductor.…”