Ion Irradiation of High-Temperature Superconductors and Its Application for Nanopatterning

Many of the cuprate high-temperature superconductors have transition temperatures well above the boiling point of liquid nitrogen and can be operated under technically viable cooling conditions. On the other hand, they have complex and sensitive crystallographic structures that impose severe restrictions for nano-patterning by the established methods. Ion irradiation of these materials offers a unique possibility to create a wide range of different defects and to tailor the electrical and superconducting properties. Depending on the species of ions used during the irradiation, their energy and fluence, nanoscale columnar pinning centres can be created that enhance the critical current, or randomly distributed point defects that change the superconducting properties. The various effects of ion bombardment on the structural and electrical properties of a representative high-temperature superconductor are reviewed with an emphasis on He

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irradiation with moderate energy and the prospects discussed to create nanostructures in thin films of these superconductors.