Electric resistance and magnetoresistance of a two-layer epitaxial heterostructure (30 nm)La0.67Ca0.33MnO3/(30 nm)La0.67Ba0.33MnO3

Two-layer epitaxial heterostructures (30 nm)La0.67Ca0.33MnO3/(30 nm)La0.67Ba0.33MnO3 (LCMO/LBMO) have been grown by laser deposition on single crystal (001)LaAlO3 (LAO) substrates. In this system, the upper (LCMO) layer occurs under the action of tensile stresses in the substrate plane, whereas the lower (LBMO) layer exhibits biaxial compression. The formation of a 30-nm-thick LCMO film on the surface of the 30-nm-thick LBMO layer leads to an increase in the level of mechanical stresses in the latter layer. The maximum electric resistivity ρ of the (30 nm)LCMO/(30 nm)LBMO/LAO structure was observed at a temperature 25–30 K below that corresponding to the maximum of the ρ(T) curve for a single (30 nm)LBMO film on the same LAO substrate.