Fabrication and Physical Properties of Polycrystalline Iron-Chalcogenides Superconductors

Iron-based superconductors are an interesting class of materials that have attracted significant interest during the last years, and which could be employed in a variety of potential applications due to their high upper critical field H
_c2
. In order to exploit the properties of these materials for practical applications, in this paper we explore two different routes for the fabrication of polycrystalline samples belonging to 11-family. In particular, the influence of dedicated heat treatments has been investigated to optimize their overall superconducting properties. Then, we compared the pinning properties of these two types of samples to correlate the fabrication process with the pinning landscape. The final aim is to obtain an increased T
_c
and H
_c2
, as well as an enhanced pinning efficacy, which could lead to higher critical current density J
_c
relevant for practical uses.