Dynamic electrical response of Y1Ba2Cu3O7−x

We studied the dynamic electrical properties of epitaxial Y1Ba2Cu3O7−x superconducting thin films on strontium titanate and MgO substrates. A fast nonlinear switching of a high-Tc film between the dissipative and superconducting states has been demonstrated. These measurements show that the rise and the fall times of these transitions are faster than 250 ps (which are presumably limited by the speed of the measurement electronics). This fast nonlinear switching may lead to opportunities for new high-frequency electronic devices including, for example, fast logic gates or threshold devices. We have proposed and demonstrated the application of such a nonlinear switching in a novel noise discrimination scheme for speeds of several hundred MHz. The proposed method is simple and effective in the enhancement of signal-to-noise ratio in digital electronic circuits.