DC SQUIDS based on YBaCuO nanobridges

摘要

DC SQUIDs based on YBaCuO thin film nanobridges have been investigated. Critical current densities J_c are up to 3-10~6A/cm~2 at T=77 K and follow J_c∝(1-T-T_c)~(1.6±0.1) High values of the voltage-flux modulation are observed (8μV peak to peak at 77 K). A temperature dependence of the SQUID modulation found to be essentially different from the one of the conventional weak link SQUID. We discuss our devices by considering degradation of the nanobridge area during structuring, which leads to a transition from SNS to SS'S type junction with decreasing temperature.