MICROWAVE RESPONSE OF YBACUO THIN-FILM DAYEM BRIDGES

1-μm-wide Dayem bridges were patterned with a pulsed Xe laser in c-axis-oriented YBaCuO films prepared according to the BaF2 method. The microbridges have a critical current density of 2×106 A/cm2 at 77 K, which is typical for an epitaxial film without grain boundaries. When microwave radiation in the centimeter wavelength range is applied, we observe current steps in the current-voltage characteristic up to 72 K. The dependence of these steps on microwave power is compared with the model of Golovashkin and Lykov {Zh. Eksp. Teor. Fiz. 74, 214 (1978) [Sov. Phys. JETP 47, 110 (1978)]}; we find that the step amplitude is smaller than predicted.