FLUX PINNING IN Y1-XPRXBA2CU3O7-DELTA HIGH-TC SUPERCONDUCTORS

Magnetic relaxation measurements have been made on two sets of samples of Y1-xPrxBa2Cu3O7-delta high T(c) superconductors with 0 less-than-or-equal-to x less-than-or-equal-to 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 almost-equal-to 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.