Vortex motion and Josephson effect in superconducting microbridges in (001) and (105) oriented YBaCuO thin films

Microbridges with dimensions smaller than the effective penetration depth have been prepared in epitaxially grown

Superconducting quantum interference devices based on YBaCuO nanobridges

Direct current SQUIDs based on YBaCuO thin film nanobridges have been investigated. Critical current densities Jc of the devices are up to 3 × 106 A/cm2 at T=77 K and show a temperature dependence of (1 ¿ T/Tc)1.6 ± 0.1. High values of the voltage-flux modulation are observed (8 µV peak to peak at 77 K, 45 µV at 4.2 K). The temperature dependence of the SQUID modulation is found to be essentially different from the one of the conventional weak link SQUID. We discuss our results by considering degradation of the nanobridge area during structuring, which leads to a transition from SNS to SS[prime]S type junction with decreasing temperatur

Weak link properties of YBa2Cu3O7 nanostructures

YBa2Cu3O7 bridges with widths ranging from 50nm to 3 micrometers were made using electron beam lithography and focused ion beam milling. The current voltage characteristics of the nanobridges show, under microwave irradiation, pronounced Shapiro steps up to the transition temperature. SQUIDs, using these nanobridges, have been made and flux to voltage modulation up to 85K was observed, with a maximum modulation depth of 8 (mu) V at 77K. An unusual temperature dependence of the modulation is observed, which can be explained by assuming an exponential spatial distribution of the superconducting properties near the edge of a superconductor