DEFECT PRODUCTION AND RECOVERY IN HIGH-T-C SUPERCONDUCTORS IRRADIATEDWITH ELECTRONS AND IONS AT LOW-TEMPERATURE

We have measured the fluence dependence of the electrical resistance a t normal-state (100 K) and the critical temperature, T-c, in the high- T-c superconductor EuBa2Cu3Oy irradiated with 2 MeV electrons and vari ous ions (H, He, C. Ne, and Ar) with energies from 0.5 to 2 MeV. The d efect production rate, which is obtained from the initial slope of the resistance-fluence curve, is almost proportional to the nuclear stopp ing power, S-n. The T-c depression due to irradiation is also nearly p roportional to S-n. These results indicate that the defect production process is dominated by elastic displacement and does not depend stron gly on the energy spectrum of primary knock-on atoms (PKA). Successive annealing up to 300 K after irradiation results in a significant reco very of normal-state resistance and T-c. This result suggests that low temperature irradiation is necessary for determining the nature of da mage produced in high-T-c. superconductors which will be used for appl ication under superconducting state. (C) 1998 Elsevier Science B.V. Al l rights reserved.