X-ray irradiation as an improvement technique for oxygen ordering and enrichment of YBa2Cu3O7 − x single crystals

The effects of X-ray irradiation on as-grown YBa2Cu3O7 − x single crystals were investigated, in order to test the effects of radiation-induced defects during the subsequent annealing in O2, and to verify if short-circuits for diffusion could be provided that improve the oxygen enrichment of the specimens. X-ray irradiation was found to have a favourable effect on the homogeneity of the oxygen enrichment of the samples, as stated by the high reproducibility of resistance measurements carried out on specimens grown, irradiated and annealed under the same conditions. Even if X-ray irradiation seems unable to determine a significant reduction of the time needed for annealing, and it could not consequently be regarded as a totally resolutive step during the production of high-quality monocrystalline superconductors, the observed homogenization of lattice oxygen distribution seems to be exploitable.