Engineering short-segmented columnar defects in seconds for 20 MA/cm2 supercurrent density in iron-based superconductors

Realizing ultra-high supercurrent density in iron-based superconductors (IBS) is a crucial step toward practical applications at high magnetic fields. However, engineering the most effective pinning structure to maximize the critical current density (J_c) remains an open challenge. In this work, Ba_1-xK_xFe₂As₂ single crystals were irradiated by Xe ions within seconds, achieving a high J_c of 20 MA/cm² at 2 K. Remarkably, the J_c remains 8.7 MA/cm² at 5 K and 4 T, which surpasses previously reported values of IBS at high-fields. This enhancement is attributed to the replacement of intrinsic weak collective pinning by strong pinning of segmented discontinuous columnar defects. The advantageous pinning landscape minimizes superconductivity degradation and efficiently suppresses the motion of vortex kinks across a wide temperature range. The J_c (25 K, 5 T) is enhanced to 1.2 MA/cm², which is nearly 180 times that of the unirradiated sample. These findings pave the way for further J_c enhancement by optimizing the defect geometry and density, providing valuable insights for the development of high-performance superconducting materials.