Crossed-film cryotron switching speed

To date there have been no direct measurements of the switching speed of an individual crossed-film cryotron (CFC) due to the extremely low gate resistance of the device in its normal state. A method which is, in principle, similar to conventional sampling techniques is used to determine the CFC switching speed with a 2-ns time resolution and a gate resistance sensitivity of 0.1 μΩ. CFC switching speeds are determined as a function of control current overdrive and gate current. In this way, the gain-bandwidth limitations of the device are experimentally determined. These data can be used to determine the optimum speeds of CFC logic circuits.