Interface effects on the electronic transport properties in highly epitaxial LaBaCo₂O_5.5+δ films

Single-crystalline perovskite LaBaCo₂O_5.5+δ thin films were grown on a (110) NdGaO₃ single-crystal substrate in order to systematically investigate the effect of lattice mismatch on the electrical transport properties in comparison to the films on LaAlO₃, SrTiO₃, and MgO substrates. Microstructure studies reveal that all of the LaBaCo₂O_5.5+δ films are of excellent quality with atomically sharp interface structures. The electrical and magnetic transport property studies indicate that the resistivity, magnetoresistance, and magnetic moment of the film are very sensitive to the substrate materials because of the lattice mismatch/interface strain. The Curie temperature, however, is almost independent of the strain imposed by the substrate, probably because of the strong coupling between the nanodomain boundary and interface strain.