Giant enhancement of critical current density at high field in superconducting (Li,Fe)OHFeSe films by Mn doping*

Critical current density (J_c) is one of the major limiting factors for high-field applications of iron-based superconductors. Here, we report that Mn ions are successfully incorporated into nontoxic superconducting (Li,Fe)OHFeSe films. Remarkably, the J_c is significantly enhanced from 0.03 to 0.32MA cm⁻² under 33 T, and the vortex pinning force density monotonically increases up to 106 GN m⁻³, which is the highest record so far among all iron-based superconductors. Our results demonstrate that Mn incorporation is an effective method to optimize the performance of (Li,Fe)OHFeSe films, offering a promising candidate for high-field applications.