Y-Ba-Cu-O thin films as active high power switches

We have studied the active switching of nonshunted Y-Ba-Cu-O films. Therefore films of 10 - 300nm thickness were deposited on substrates by thermal co-evaporation. Bridges, 5mm × 26mm and 10mm × 42mm, were structured by standard photolithography. No topcoat of gold was used to retain higher switching powers. The active switching of the DC-biased Y-Ba-Cu-O-bridges was triggered by heat pulses or radio frequency. For the thermal trigger a resistive thin film heater was evaporated on the back side of the substrate. The samples were biased by currents up to 20A and triggered by heat pulses (up to 500W) at 10 - 70K. A resonant circuit was used in the case of the RF-trigger. The pan-cake coil of this circuit was placed 2mm above the 10mm wide Y-Ba-Cu-O bridge. At 77K the stripes were biased by currents up to 40A and triggered with RF-pulses of >1ms duration and 3-40 Watt (10MHz). Active switching was observed in both cases. In comparison to the thermal trigger power for RF induced switching power is very low.