1. Department of Electrical Engineering, Northeastern University, 02115, Boston, Massachusetts 2. Physics Department, Northeastern University, 02115, Boston, Massachusetts 3. Lockheed Sanders, 03061, Nashua, New Hampshire
Abstract:
A microwave superconducting magnetometer is described in which a microstrip resonator is coupled to a two-hole high-Tc thin-film SQUID device. Both the microstrip circuit and the thin-film SQUID were fabricated by photolithography techniques. The YBCO thin film was deposited on single-crystal substrate of yttria-stabilized zirconia YSZ(100)] by an ion beam sputtering technique producing a superconducting transition measured at a critical temperature ofTc=92 K to within ΔT ~ 3 K. Non linear oscillatory behavior was observed in the microstrip resonator when inductively coupled to the SQUID. This nonlinear behavior yielded a microwave device in which the reflected microwave power varied with applied DC magnetic flux.