The structure and magnetotransport properties of La2/3Sr1/3MnO3/Ba(La)TiO3 composites

The effect of Ba(La)TiO3 doping on the structure and magnetotransport properties of La2/3Sr1/3MnO3(LSMO)/xBa(La)TiO3 (x=0.0, 1.0, 5.0 mol%) have been investigated. The X-ray diffraction patterns and microstructural analysis show that BaTiO3 and LSMO phases exist independently in BaTiO3-doped composites. The metal–insulator transition temperature (TMI) decreases whereas the maximum resistivity increases very quickly by the increase of BaTiO3 doping level. The partial substitution of Ba by La(0.35 mol%) results in a decrease in resistivity of LSMO/xBa(La)TiO3 composites. Magnetoresistance of BaTiO3-doped composites decreases monotonously in the temperature range 200–400 K in a magnetic field of 5 T, which is completely different from that of LSMO compound. The value of MR decreases at low field (H<1 T) and increases at high fields (H>1 T) with increasing the BaTiO3 doping level at low temperatures below 280 K. These investigations reveal that the magnetotransport properties of LSMO/xBa(La)TiO3 composites are dominated by spin-dependent scattering and tunneling effect at the LSMO/BaTiO3/LSMO magnetic tunnel junction.