Long-time stable and high-performance YBa2Cu3O7 nanoSQUIDs with more interfaces

We report on the fabrication and characterization of nanopatterned superconducting quantum interference devices (SQUIDs) based grain boundary Josephson junctions in epitaxially grown multilayer YBa2Cu3O7 (YBCO)/SiTrO3 (STO) thin films. Nanopatterning is performed by Ga+ focused ion beam milling. The evolution electric transport noise properties YBCO nanoSQUIDs over a time span more than one year are recorded analyzed. find that YBCO/STO show stable high performance time. critical current decreases within ∼40 days 30%–50% then remains almost constant without obvious decline trend for with STO layer as interface even 380 days, which demonstrates superiority capping layer. Moreover, we have about an order magnitude smaller low-frequency excess flux (compared to similar single devices) root-mean-square spectral density ∼5–6 µΦ0/Hz1/2 at 1 Hz. For device, does not degrade three months.