Properties of DC SQUIDs Made from YBCO and TBCCO Films

Double-microbridge dc superconducting quantum interference devices (SQUIDs) have been fabricated from the postannealed Y1Ba2Cu3Oy and Tl2Ba2Ca2Cu3Oy thin films by chemical etching and ion milling patterning technique. The applied magnetic field dependences of the voltage of the YBCO and TBCCO SQUIDs have been studied at temperature ranging from 4.2 to 23 K and at 77 K. The largest output voltage of the devices were 3.4 μV/Φ0 (at 5 K) for YBCO and 60 μV/Φ0 (at 77 K) for TBCCO. The properties of the output of these devices have been discussed.