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

Films of La0.5Sr0.5CoO3 (LSCO) have been deposited on specially treated TiO 2-terminated (001) SrTiO3 substrate surfaces and on macroporous polycrystal line alpha-Al2O3 substrates, having a mean pore diameter of 80 nm, by pulse d laser deposition. The films deposited on SrTiO3 are good conducting, (001 )textured, and exceptionally smooth (1-2 Angstrom for 100 nm thick films). LSCO films deposited on porous alpha-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 observ ed on the porous alpha-Al2O3 substrates depending on the oxygen pressure du ring film deposition. Films grown at an oxygen pressure of 10(-1) mbar are :macroporous, whereas films grown at 10(-2) mbar completely cover the subst rate pores. In the latter case, strain effects lead to him cracking.