Improvement of anisotropy of superconducting properties in Y-rich YBa₂Cu₃O_y film in magnetic fields

In order to put the REBa₂Cu₃O_y superconductor into practical use, it is necessary to more isotropically improve the critical current density (J _c) with respect to an applied magnetic field angle. Therefore, artificial pinning centers (APCs) which are like a particle shape should be introduced into the superconductor. In this study, nano-particule APCs were introduced by fabricating Y₁+_xBa₂Cu₃O_y (x = 0 ∼ 1.0) thin films with excess Y composition, and effect of x, substrate temperature (T _ss) and pulsed laser repetition frequency (f _Ls) on the isotropy of J _c in the magnetic field was evaluated. As a result, these conditions proved to have a strong influence on isotropic improvement of J _c in the magnetic field. (paper)