Precipitate-free films of La1−xSrxMnO3 grown on the substrates with artificial step edges

We have fabricated precipitate-free La0.7Sr0.3MnO3 (LSMO) films by locating precipitate nucleation at artificial step edges patterned on SrTiO3 substrates and absorbing excess species of off-stoichiometry by getter effect. The precipitate-free and atomically flat area of about 10μm width can be obtained along the step edges by pulsed-laser deposition at a substrate temperature Ts of ∼900°C. Thermally activated processes are shown to be involved in such chemical reactions between the precipitates and surface migrating species. LSMO∕SrTiO3∕LSMO tunnel junctions fabricated by this method showed an excellent uniformity of the junction resistances.