Abstract:
The noise performance of thin film YBa2Cu3O7 x (YBCO) directly coupled superconducting quantum interference
device (SQUID) magnetometers fabricated on MgO substrates with step-edge junctions was investigated at 77 K in
static magnetic fields. Dc SQUID magnetometers with solid pick-up loops and with meshed structures consisting of
narrow (64 lm) lines were compared. Our measurement results showed that solid structure dc SQUID magnetometers
have comparable noise performance to those employing a meshed structure when operated in external magnetic fields.
Neither our solid nor meshed dc SQUID magnetometers showed a significant rise in low-frequency noise in the presence
of a field as large as 120 lT. The impact of YBCO film morphology was also found to influence the 1=f noise performance.
