High-quality YBa2Cu3O7-x nanobridges fabricated by FIB etching

Nanostructuring of YBa2Cu3O7-x films is a challenging task on a way to the high-quality YBa2Cu3O7-x nanodevices because of the sensitivity of YBa2Cu3O7-x thin films to the patterning process. In this work we report on a "cold" nanopatterning procedure used for the structuring of the ultra-thin YBa2Cu3O7-x films by focused ion beam etching with a specially developed protection layer, which can be easily removed after the patterning process without any damage to the ultra-thin YBa2Cu3O7-x film. Highquality ultra-thin YBa2Cu3O7-x nanobridges, fabricated with this nanopatterning procedure, demonstrated nearly the same values of the critical temperature and the transition width as an original film for bridge widths down to 150 nm. High critical current densities up to 125 MA/cm have been achieved at T = 8 K. The observed dependence of the critical current density on the width and the thickness of nanobridges was consistent with the edge barrier model.