Irradiation-free, columnar defects comprised of self-assembled nanodots and nanorods resulting in strongly enhanced flux-pinning in YBa2Cu3O7−δ films

摘要: The development of biaxially textured, second-generation, high-temperature superconducting (HTS) wires is expected to enable most large-scale applications HTS materials, in particular electric-power applications. For many potential applications, high critical currents applied magnetic fields are required. It well known that columnar defects generated by irradiating materials with heavy ions significantly enhance the in-field current density. Hence, for over a decade scientists world-wide have sought means produce such without expense and complexity ionizing radiation. Using simple practically scalable technique, we succeeded producing long, nearly continuous vortex pins along c-axis YBa2Cu3O7?? (YBCO), form self-assembled stacks BaZrO3 (BZO) nanodots nanorods. nanorods diameter ~2?3?nm an areal density ('matching field') 8?10?T 2?vol.% incorporation BaZrO3. In addition, four misfit dislocations around each nanodot or nanorod aligned act as extended defects. YBCO films exhibit enhanced pinning less sensitivity H. particular, at intermediate field values, density, Jc, varies Jc~H??, ?~0.3 rather than usual values 0.5?0.65. Similar results were also obtained CaZrO3 (CZO) YSZ within YBCO, indicating broad applicability developed process. process could be used incorporate matrices other different materials.