Flux pinning properties of TFA-MOD (Y,Gd)Ba₂Cu₃O_<i>x</i>tapes with BaZrO₃nanoparticles

Abstract

A high critical current density Jc with a nearly isotropic angular dependence at 77.3 K was recently obtained by the introduction of nanoparticles to (Y,RE)Ba2Cu3Oy (RE123, RE = Sm, Gd)-coated conductors prepared by trifluoroacetate metal–organic deposition (TFA-MOD). The flux pinning properties were evaluated on the basis of detailed measurements of the upper critical field, the irreversibility field and the critical current density of the TFA-MOD RE123-coated conductor. We found that strong random pinning by the BaZrO3 nanoparticles and weak c-axis correlated pinning by twin boundaries functioned cooperatively in nanoparticles introduced to (Y, Gd)123-coated conductors prepared by TFA-MOD. The coexistence of two different pinning centers played an important role in the nearly isotropic angular dependence of Jc.