No abstract

We report ordering of the cobalt electron configuration in ferromagnetic strained epitaxial LaCoO_{3}. Specifically, the presence of charge order is demonstrated from distinct features of the resonant cobalt contribution to superstructure reflections. Density functional theory calculations show that the observed order is consistent with the spin-state periodicity predicted to give rise to ferromagnetism in LaCoO_{3}. Through the modification of symmetry by strain, concurrent frozen charge and spin-state order are stabilized, giving rise to long-range magnetic order.

We explore manganite interface magnetism in epitaxially grown La 0.7 Sr 0.3 MnO 3 ͑LSMO͒ / SrTiO 3 ultrathin superlattices ͑SL͒ along ͑110͒ orientation. We show that robust ferromagnetism persists down to 4 monolayers ͑MLs͒ LSMO ͑ϳ1.1 nm in thickness͒, of which 50% Mn is at the interface state. Above 8 MLs, the magnetic moment is nearly saturated to the theoretical value of 3.7 B with an estimated interface moment of 3.2 B . In comparison to ͑100͒-oriented SLs which were previously shown to have a spin-canted ground state, ͑110͒oriented SLs exhibit stronger low-dimensional ferromagnetism and better metallicity, suggesting a ferromagnetic-interface spin state well suited for all-oxide spintronic devices. The underlining mechanism is qualitatively discussed.