Pinning Improvement of A15 Applied Superconducting Materials

Abstract

Electron-phonon coupling is one of the most common interaction in superconducting materials ranging from Nb3Sn, MgB2, iron-based superconductors and high temperature cuprates such as YBa2Cu3O 7−δ and HgBa2Ca2Cu3O 8+δ . However an importance of the electron-phonon coupling constant, λep, should not be underestimated for characterisation of the electronic properties of superconducting materials, but it is important that the enhanced flux pinning mechanism can be hold responsible for the applicability of the A15 superconducting materials in emerging hydrogen cryomagnetic technology where temperature of the liquid H2 can be as low as 14 K.

Advances in Development of Powder-in-Tube Nb3Sn, Bi-Based, and MgB2 Superconducting Conductors

“…(1) and Eq. (2) of the Nb 3 Sn layers which will not shift the maximum pinning force towards the higher magnetic flux density [6]:…”

“…Grain boundary pinning related mechanism is difficult to change, however there are new possible elaborated approaches that can be further developed [6,7]. The voids formation in the central core cannot be avoided but can be reduced by implementation of combination of the compositional and architectural changes in the initial filamentary core and also by application of in situ external pressure during sintering as it will be discussed in the following sections concerning Bi-based and MgB 2 PIT superconductors.…”

Can iron-based superconductors become the next generation of coated conductors?

“…However, because the effect of each pinning site is influenced by the fundamental properties of the specific superconducting system, the approach to increase the in-field J c also depends on the type of superconducting material. For instance, grain boundaries are one of the most effective pinning sources for conventional superconductors, such as MgB 2 and Nb 3 Sn [7,8]. However, they cause J c to deteriorate in high-T c cuprate superconductors (HTSs) owing to the weak-link problem [9].…”