SPIN-POLARIZED QUASI-PARTICLE INJECTION DEVICES USING AU YBA2CU3O7/LAALO3/ND0.7SR0.3/MNO3 HETEROSTRUCTURES/

Oxide heterostructures were used for studies of quasiparticle injectio n effects in high-T-c superconducting thin films. The effect of inject ion of spin polarized quasiparticles from a ferromagnetic gate layer w as compared to that of unpolarized quasiparticles from a nonmagnetic m etallic gate. Transport measurements of the superconducting layer show ed strong suppression in the supercurrent by the injection of spin-pol arized quasiparticles, and a current gain of as large as five was atta ined. This is 10 to 30 times larger than the gain of unpolarized injec tion devices. Such large effects could be useful in a variety of activ e high-T-c superconductor/colossal magnetoresistance heterostructure b ased devices. (C) 1997 American Institute of Physics.