Spin-polarized quasiparticle injection devices using Au/YBa2Cu3O7/LaAlO3/Nd0.7Sr0.3/MnO3 heterostructures

Oxide heterostructures were used for studies of quasiparticle injection effects in high-T-c superconducting thin films. The effect of injection of spin polarized quasiparticles from a ferromagnetic gate layer was compared to that of unpolarized quasiparticles from a nonmagnetic metallic gate. Transport measurements of the superconducting layer showed strong suppression in the supercurrent by the injection of spin-polarized quasiparticles, and a current gain of as large as five was attained. This is 10 to 30 times larger than the gain of unpolarized injection devices. Such large effects could be useful in a variety of active high-T-c superconductor/colossal magnetoresistance heterostructure based devices. (C) 1997 American Institute of Physics.