Discrete underdamped vortex flow devices

Vortex flow devices consisting of discrete arrays of underdamped Josephson junctions have been fabricated and measured. These devices and their long, continuous junction counterparts are based on the ability to magnetically control the Eck voltage in an underdamped system. We find that both transistor and oscillator parameters are improved by placing the arrays above a superconducting ground plane and by connecting two arrays in series. We developed models for the device behavior which numerically account for the measured parameters. Our models also suggest that junctions with smaller capacitances will further improve the device parameters.<>