Flux pinning in Y1 - xPrxBa2Cu3O7 - delta high Tc superconductors

Magnetic relaxation measurements have been made on two sets of samples of Y_1-xPr_xBa₂Cu₃O_7-δ high T_c superconductors with 0≤x≤0.10. The samples were prepared as fibers using a sol-gel process and as polycrystalline pellets using a standard solid-state reaction technique. In an applied field of 5 kOe at 30 K, the fluxoid pinning potential U was observed to increase approximately linearly with Pr concentration x at the rate dU/dx≊1 eV. A mechanism for the enhancement of U may be the suppression of the superconducting order parameter in the vicinity of the Pr ions due to magnetic pair breaking.