Increased pinning energies and critical current densities in heavy‐ion‐irradiated Bi2Sr2CaCu2O8single crystals

We report a significant increase in the pinning energy of vortices in single‐crystal Bi2Sr2CaCu2O8 when irradiated with heavy ions such as Ar+. This is in contrast with the results of light ion (H+, He+) irradiations which give pinning energies comparable with those of unirradiated crystals. The stronger pinning is attributed to defects larger than point defects, e.g., clusters or amorphized regions. As a result of higher pinning energies, critical currents persist at markedly higher temperatures and fields.