Structural and electrical properties of La0.5Sr0.5CoO3 films on SrTiO3 and porous alpha-Al2O3 substrates

Films of La0.5Sr0.5CoO3 (LSCO) have been deposited on specially treated TiO2-terminated (001) SrTiO3 substrate surfaces and on macroporous polycrystalline !-Al2O3 substrates, having a mean pore diameter of 80 nm, by pulsed laser deposition. The films deposited on SrTiO3 are good conducting, (001) textured, and exceptionally smooth (1–2 Å for 100 nm thick films). LSCO films deposited on porous !-Al2O3 are polycrystalline and exhibit good crystallographic and electrical properties despite the large substrate roughness and the differences in lattice parameters and crystal structure between the film and the substrate. Different growth modes have been observed on the porous !-Al2O3 substrates depending on the oxygen pressure during film deposition. Films grown at an oxygen pressure of 10-1 mbar are macroporous, whereas films grown at 10-2 mbar completely cover the substrate pores. In the latter case, strain effects lead to film cracking