Enhancement of flux-line pinning in all-oxide superconductor/ferromagnet heterostructures

摘要

We have studied the local critical current density, j_c in the superconductor thin film of bilayer structures consisting of YBa_2Cu_3O_7 and the ferromagnets La_(2/3)Ca_(1/3)MnO_3 and SrRuO_3, respectively, by means of quantitative magneto-optics. A pronounced hysteresis of j_c was observed which is ascribed to the magnetization state of the ferromagnetic layer. The results are discussed within the frame of magnetic vortex - wall interactions.