Characterisation of Interface-Engineered Ramp-Edge Josephson Junctions by Transmission Electron Microscopy

摘要

Interface-engineered ramp-edge junctions (IEJ) have been characterised by high-resolution transmission electron microscopy, X-ray analysis and electron energy loss spectroscopy. The IEJ are prepared by plasma etching an ion-milled YBa_2Cu_3O_(7-8)(YBCO) ramp-edge and subsequently a top YBCO layer is deposited. The results show that the YBCO at the plasma-etched interface has a modified structure. The modified barrier structure has a pseudo cubic unit cell which is rotated 45° around the [001] axis with respect to the underlying YBCO.