The effects of Pr-doping on the critical current density in YBa2Cu3O7-δ

The effects of Pr-doping on the critical current density J(c) and the critical temperature T-c in YBa2Cu3O7-delta (YBCO) have been investigated. In spite of the monotonic decrease in T-c with increasing Pr-concentration (x), the increasing of J(c) occurs as a field is applied and J(c) displays a maximum at a certain x. Moreover, this maximum shifts to lower x by increasing fields. The characteristic behavior of J(c) with Pr-doping can be explained in terms of the counterbalance of two different effects simultaneously caused by Pr-doping: the suppression of matrix superconductivity which leads to the decrease in depairing critical current density J(0), and the formation of nanometric inhomogeneity which leads to the enhancement of pinning force. (C) 2002 Elsevier Science B.V. All rights reserved.