Thermomigration tuning of YBa(Formula presented) (Formula presented)Cu(Formula presented) (Formula presented)O(Formula presented) (Formula presented)grooved Dayem nanoBridge-based SQUIDs

Journal article, 2026

Thermomigration (TM) is an ex-situ technique that enables tuning of the transport properties in YBa (Formula presented) (Formula presented) Cu (Formula presented) (Formula presented) O (Formula presented) (Formula presented) -based nanostructures by driving oxygen migration through local Joule heating. We apply an AC current bias to conduct TM on grooved Dayem nanoBridge (GDB)-based Superconducting Quantum Interference Devices (SQUIDs) and investigate its impact on transport characteristics via current–voltage and voltage modulation measurements. By adjusting both the timing and amplitude of the applied AC bias, we identified two distinct TM modes: a ‘hard’ regime, characterized by high-bias, rapidly repeated AC-current bursts that reduce the critical current, and a ‘soft’ regime, in which lower-bias bursts separated by longer waiting times selectively tune the differential resistance at the operating point. Both tuning methods significantly enhance device performance, with voltage modulation improvements higher than a factor 5. Our findings confirm TM as a powerful post-fabrication tool for optimization of the transport properties of GDB-based high temperature superconductor SQUIDs.