X-RAY-IRRADIATION AS AN IMPROVEMENT TECHNIQUE FOR OXYGEN ORDERING ANDENRICHMENT OF YBA2CU3O7-X SINGLE-CRYSTALS

The effects of X-ray irradiation on as-grown YBa2Cu3O7-x single crysta ls were investigated, in order to test the effects of radiation-induce d defects during the subsequent annealing in O-2, and to verify if sho rt-circuits for diffusion could be provided that improve the oxygen en richment of the specimens. X-ray irradiation was found to have a favou rable effect on the homogeneity of the oxygen enrichment of the sample s, as stated by the high reproducibility of resistance measurements ca rried out on specimens grown, irradiated and annealed under the same c onditions. Even if X-ray irradiation seems unable to determine a signi ficant reduction of the time needed for annealing, and it could not co nsequently be regarded as a totally resolutive step during the product ion of high-quality monocrystalline superconductors, the observed homo genization of lattice oxygen distribution seems to be exploitable. (C) 1998 Chapman & Hall.