The record J_c of Nb₃Sn conductors has been at a plateau since the early 2000s; however, much higher J_c than the state of the art is required for future energy-frontier circular colliders. For example, the non-Cu J_c required by the planned Future Circular Collider (FCC) is ~50% higher than what present Nb₃Sn conductors can deliver. In the past few years a new type of Nb₃Sn conductors with artificial pinning centers (APC) have demonstrated significantly superior performance relative to the state of the art. Such APC wires are based on the internal oxidation method, which generates nano-size oxide particles in Nb₃Sn. It was found that this method improves high-field J_c via four mechanisms: (1) refining Nb₃Sn grain size, (2) the particles directly serving as flux pinning centers, (3) shifting flux pinning force (F_p-B) curve peak to higher field, (4) enhancing B_irr and B_c2. In 2019 the APC wires we developed first reached the FCC J_c specification. Since then the efforts have been mainly focused on pushing the APC wires toward readiness for practical applications, including improvement of stability. In this talk a comprehensive review of the APC Nb₃Sn conductors will be given, including its opportunities, challenges, current status and future plans.

Keywords: Nb3Sn, Artificial Pinning Center, APC, Internal Oxidation