摘要：SummaryIron-based superconductors are expected to be used in strong magnet applications owing to their excellent superconducting properties. The process of sintering a mechanically alloyed precursor powder is effective in achieving a high upper critical field and critical current density in BaFe2As2(Ba122) polycrystalline bulk materials. However, when this process is applied to K-doped Ba122, which shows the highest critical temperature in the Ba122 family, suppressing the vaporization of potassium is challenging. In this study, spark plasma sintering (SPS) method was applied to K-doped Ba122 to achieve fast densification. In contrast to the conventional synthesis method, which requires several tens of hours, optimally K-doped bulks with near theoretical density were obtained after only 5 min of SPS, and the magnetic critical current density reached 105A/cm2at 5 K. The demonstrated superconducting properties suggest that this fast densification technique is a useful tool for applying K-doped Ba122 to bulk trapped field magnets.Graphical abstractDisplay OmittedHighlights•K-doped Ba122 polycrystalline bulks were synthesized via spark plasma sintering•Nearly single-phase and highly dense bulks were obtained in short period (5 min)•The magnetic critical current density exceeded 105A/cm2at 5 KCondensed matter physics; Superconductivity; Transport property of condensed matter
