CHARACTERISTICS OF HIGH-TC SUPERCONDUCTING FLUX-FLOW TRANSISTORS WITH SUBMICRON CHANNELS

High-Tc superconducting flux flow transistors were fabricated by focused ion-beam irradiation with thin films of co-evaporated YBaCuO. The line-shaped vortex flow channels (0.8 mu m in width) were constructed by scanning a focused Ga ion-beam (500 nm in diameter) to reduce the critical super-current of the film. The three terminal characteristics of the device were successfully measured. The flux flow characteristics and the transresistance of the submicron channel device were measured and compared with those of an ordinary device with a channel wider than 2 mu m. The measured flow voltage, transresistance and current gain are discussed in relation to the parallel flow of the vortices in the wide channel.