The development of helium ion beam-fabricated Josephson junctions represents a transformative breakthrough for high-temperature superconducting (HTS) electronics. These junctions exhibit well-defined insulating barrier characteristics and improved performance compared to earlier HTS junction technologies. Beyond their application in circuit fabrication, these junctions enable in-plane tunneling spectroscopy, offering new insights into the anisotropic transport properties of YBa₂Cu₃O₇₋δ (YBCO). By leveraging this understanding, we can design circuits that are more resilient to the detrimental effects of anisotropy, improving the robustness and scalability of HTS devices.
These advances coincide with significant progress in HTS thin film growth. Reactive co-evaporation (RCE) now enables the deposition of large-area, high-quality YBCO thin films with improved uniformity and reduced defect densities, overcoming previous limitations in material scalability. Together, these breakthroughs provide a compelling case for revisiting HTS superconducting electronics, enabling new opportunities in nanoscale superconducting quantum interference devices (nanoSQUIDs) for ultra-sensitive detection and quantum flux parametron (QFP) logic for energy-efficient computing. The combination of precision junction fabrication and high-quality thin films sets the stage for a new generation of high-Tc superconducting circuits with applications in quantum sensing and cryogenic computing.