Spin-polarized quasiparticle injection effect in MOCVD-grown YBa2Cu3O7/SrTiO3/La1-xSrxMnO3 heterostructures

Metal oxide heterostructures consisting of the ferromagnetic La1-xSrxMnO3 ( x approximate to 0.3) underlayer, thin (d congruent to 5-10 nm) SrTiO3 barr ier layer and YBa2Cu3O7 cap layer were grown on single crystal LaAlO3 (1 0 0) substrates at 825 degreesC under oxygen pressure of about 200 Pa by sing le source pulsed injection MOCVD method. The technological conditions were optimized in order to improve crystallinity and surface quality of the cons tituent layers. Wet etching was applied to form tape-like superconducting f ilms for investigation of both longitudinal and transverse electrical trans port in the heterostructures. Significant suppression of supercurrent has b een found by injecting tunneling spin-polarized current from the underlying FM layer. (C) 2001 Elsevier Science B.V. All rights reserved.