  The control of matter properties (transport, magnetic, dielectric,...) using
synthesis as thin films is strongly hindered by the lack of reliable theories,
able to guide the design of new systems, through the understanding of the
interface effects and of the way the substrate constraints are imposed to the
material. The present paper analyses the energetic contributions at the
interfaces, and proposes a model describing the microscopic mechanisms
governing the interactions at an epitaxial interface between a manganite and
another transition metal oxide in perovskite structure (as for instance $\rm
SrTiO_3$). The model is checked against experimental results and literature
analysis.
