Nano-structuring on the surface of high Tc-superconductors by STM\&AFM

We demonstrate local insulation on a cleaved surface of Bi- 2212 single crystals using a local anodic oxidation by a atomic force microscope (AFM) and a scanning tunneling microscope (STM) for the first time. We have investigated the electrical properties of the modified region by using an STM-assisted near- field microwave microscope. From the experimental observations, we conclude that the modified region becomes an insulator with an associated dielectric loss locally. Varying the applied bias- voltage and the scanning speed can control the protrusion height and the line width of the regions. This provides a potential technique for reproducibly fabricating high temperature superconducting devices with stable electronic characteristics.