Step angle effects in YBa2Cu3O7 step-edge Josephson junctions prepared an sapphire substrates

摘要

YBa2Cu3O7 (YBCO) step edge Josephson junctions were fabricated on sapphire substrates. The steps were formed on r-plane sapphire substrates by using Ar-ion milling with PR masks. The step angle was controlled in the wide range from 20 degrees to 70 degrees by adjusting both the Ar-ion incident angle and the PR mask rotation angle relative to the incident Ar-ion beam. CeO2 buffer lays and in situ YBCO thin films were deposited on the stepped r-plane sapphire substrates by pulsed laser deposition. The: YBCO film thickness was varied to obtain the ratio of film thickness to the step height in the range from 0.5 to 1. The step-edge junction exhibited RSJ-like behavior with ICRN product of 100 similar to 300 muV, critical current density of 10(3)similar to 10(5) A/cm(2) at 77 K. [References: 3]