Magnetroresistance and Current-voltage Characteristics in La_(2/3)Sr_(1/3)MnO_3/ZnO Composite Films

Magnetroresistance and current-voltage characteristics of the composite(La2/3Sr1/3MnO3)x/(ZnO)1-x films prepared by the pulsed laser deposition method on Si(100) substrates oxidized by SiO2 were investigated.XRD patterns indicate that ZnO and LSMO have(002) and(101) dominant orientations,respectively,and they form the coexisting system of two phases.Experimental results show the film with x=0.3 favors a semiconductive conduction and the film with x=0.4 exhibits the typical insulator-metal(I-M) transition.The films have the low field magnetoresistance(LFMR) effect and the nonlinear current-voltage characteristics.The maximum LFMR value of the film with x=0.3 is about 28.8% at T=60K under an applied magnetic field of about 0.7T.The current-voltage fitting shows that a great number of interface states appear at the depletion between La2/3Sr1/3MnO3 and ZnO grains due to the mismatch of the lattice.