Gold nanocrystals in high-temperature superconducting films: creation of pinning patterns of choice

One of the major drawbacks for applications of high-temperature superconducting films is that magnetic flux is not completely expelled but penetrates the film in the form of flux vortices. Any motion of these vortices is accompanied by magnetic noise and prevents larger supercurrents. Thus, an effective pinning of flux vortices is a prerequisite for applications based on thin films of high-temperature superconductors such as coated conductors or magnetic sensor devices. However, particular superconducting structures such as tunnel barriers or flux guides suffer from increased pinning forces. We report that adding thin gold layers to the production process of epitaxial films of the high-temperature superconductor YBa2Cu3O7-delta allows the fabrication of superconducting films with spatially varying flux pinning properties. This paves the way for an easy realization of custom tailored current carrying capabilities in arbitrary patterns. Critical current densities of already strong pinning films can be locally enhanced up to 150% to prepare a material of choice at a position of choice for the realization of high-quality electronic devices with improved performance.