Fabrication of YBa2Cu3O7-delta/SrTiO3/La0.7Sr0.3MnO3-delta junctions for the control of supercurrent by spin-polarized quasiparticle current injection

Supercurrent suppression by the injection of spin-polarized quasiparticle c urrent from a ferromagnet into a superconductor is demonstrated in YBa2Cu3O 7-delta/SrTiO3/La0.7Sr0.3MnO3-delta junctions at 77 K. Negative current gai ns as large as 35 have been observed. The magnitude of the effect depends o n the net polarization of the injection current, film resistivities, barrie r microstructure, and injection geometry. Fabrication of the junctions is d iscussed in terms of optimizing these parameters for maximum supercurrent s uppression. (C) 1998 American Institute of Physics.