Researchers explore high-temperature superconductors for advanced electronics

Researchers are investigating the use of high-temperature superconductors to create more advanced electronic components, specifically Josephson junctions, which are fundamental to superconducting electronics. While junctions made from conventional superconductors are well-established, developing reproducible devices using high-temperature superconductors has presented challenges.

This recent work focused on the growth, fabrication, and electrical characterization of DyBa₂Cu₃O₇₋ₓ (DBCO) /SrTiO₃ (STO) /DBCO trilayer heterostructures. These structures are being explored for their potential in Josephson junction applications.

The research team began by optimizing the growth of YBa₂Cu₃O₇₋ₓ (YBCO) films, achieving reproducible results with a zero-resistance critical temperature (Tc) of 92 K and a maximum Tc of 89 K. These optimized growth conditions were then applied to DBCO, yielding reproducible superconducting films with Tc values around 80 K.

DBCO/STO/DBCO trilayers were grown using molecular beam epitaxy. To protect the surface and aid in subsequent device fabrication and electrical contact, the layers were capped in situ with gold. The trilayers were then patterned into mesa devices through photolithography and reactive ion etching.

Electrical characterization included measurements of room-temperature resistance, resistance versus temperature, and differential conductance. Although the experiments did not yet demonstrate Josephson junction behavior, the research established a complete workflow. This workflow covers ReBCO trilayer growth, gold capping, device fabrication, and electrical characterization, laying a foundation for future efforts to optimize high-temperature superconducting Josephson junctions.