All high T c edge-geometry weak links utilizing Y-Ba-Cu-O barrier layers

Abstract

High quality YBa2Cu3O7−x /normal‐metal/YBa2Cu3O7−x edge‐geometry weak links have been fabricated using nonsuperconducting Y‐Ba‐Cu‐O barrier layers deposited by laser ablation at reduced growth temperatures. Devices incorporating 25–100 Å thick barrier layers exhibit current‐voltage characteristics consistent with the resistively shunted junction model, with strong microwave and magnetic field response at temperatures up to 85 K. The critical currents vary exponentially with barrier thickness, and the resistances scale linearly with Y‐Ba‐Cu‐O interlayer thickness and device area, indicating good barrier uniformity, with an effective normal metal coherence length of 20 Å.