Spin polarization transport in ZnO/La2/3Sr1/3MnO3/LaAlO heterostructures

ZnO/La2/3Sr1/3MnO3 thin fims have been epitaxially grown on LaAlO3 (100) substrates using a pulsed laser deposition (PLD) method. I-V curves of the ZnO/La2/3Sr1/3MnO3 structure were investigated over the temperature range from 50 to 300 K. Analysis of the leakage current demonstrates that Poole-Frenkel emission is the dominant mechanism in our sample. The photoinduced resistance and demagnetization versus temperatures demonstrates that the optical field dominated the photoconductivity mechanism below Curie temperature Tc from different green-light source. The shape and size of the barrier were changed by junction interface and interface tensile strain due to optical and magnetic external perturbations which the photoinduced characteristics modified the carrier density at the ZnO/LSMO interface. Magnetoresistance (MR) and photoinduced resistance effect is observed and the MR is related to the electron spin-dependent scattering and the interface resistance of the heterostructure. Moreover, the La1-xSrxMnO3/ZnO heterostructure exhibited a positive colossal magnetoresistance (MR) effect over the range of 50-300 K.