Strong interfacial magnetic coupling in epitaxial bilayers of LaCoO3/LaMnO3 prepared by chemical solution deposition

We report the synthesis of high quality epitaxial bilayers of LaMnO3/LaCoO3 (LCO/LMO) on (001) LaAlO3, by spin-coating of a polymeric aqueous solutions. The bilayer shows a very large increase of the magnetization coercive field (≈ 3000%) with respect to the isolated LMO or LCO films. We suggest that the origin of this effect is a strong Mn4 +-O-Co2 + exchange interaction at the interface. Our results demonstrate that a simple chemical method is able to produce high quality epitaxial heterostructures in which interfacial effects can modify substantially the properties of the individual layers.