Minute doping with deleterious rare earths in YBa2Cu3O7−δ films for flux pinning enhancements

Abstract

To enhance the critical current density of YBa2Cu3O7−δ films, flux pinning centers are intentionally added to inhibit flux flow in applied magnetic fields. Here we provide an initial demonstration that the incorporation of very minor additions (⩽1% of Y as opposed to the 10%–40% in standard substitutions) of typically deleterious rare earths into high quality YBa2Cu3O7−δ thin films provides significant improvement of the film’s in-field current density. This is accomplished without reoptimization of the deposition parameters. Instead of site substitution for Y as might be expected, the deleterious rare earths potentially result in the formation of nanoparticulates.