YBa/sub 2/Cu/sub 3/O/sub 7/ nano-bridge junctions and dc SQUIDs made by focused ion beam milling

YBa/sub 2/Cu/sub 3/O/sub 7/ nano-bridges with widths ranging from 200 to 800 nm were made using Focused Ion Beam milling. The I-V characteristics of the narrowest nano-bridges show, under microwave irradiation, pronounced Shapiro steps up to the transition temperature. An inductively shunted single layer SQUID, using these nano-bridges, has been realised by a combination of Focused Ion Beam milling and selective epitaxial growth. Flux to voltage modulation up to 82 K was observed, with a maximum modulation depth of 3.7 /spl mu/V at 78 K.>