Proton irradiation effects on granular high-TC superconductors: Gd1-xPrxBa2Cu3O7-δ

The magnetic and proton energy Ep dependence of the pinning energy U and critical current density have been investigated in polycrystalline Gd1-xPrxBa2Cu3O7-δ samples irradiated by protons, where 0 ≤ x ≤ 0.15. The resistivity measurements in the magnetic field H up to 10 kOe indicate that the β exponent in Ueff ∝ Hβ is independent of the Pr-doping value x for the unirradiated samples, but rises as the energy of the irradiating protons increases. The slope of the exponent α in Ueff ∝ Epα(H) versus H is independent of x. In addition, some of the effects of proton irradiation have been compared with those of Pr-doping in creating effective pinning centers. I-V measurements in magnetic fields up to 15 kOe indicate that the critical current density increases as the energy of the protons increases for all samples, and remains constant with the Pr-doping values, except for the special case when x=0.1. (Abstract Copyright [2002], Wiley Periodicals, Inc.)