  We report on first principles calculations of the electronic structure of
La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/SrTiO$_{3}$ junction with two possible types of
interface terminations. We find that the La$_{0.7}$Sr$_{0.3}$O/TiO$_{2}$
interface preserves the interlayer ferromagnetic coupling between the interface
MnO$_{2}$ layer and the bulk. The other interface, MnO$_{2}$/SrO, favours
antiferromagnetic coupling with the bulk. By inserting two unit cells of
undoped LaMnO$_{3}$ at the interface the ferromagnetism is recovered. This is
understood in terms of the doping level and the mobility of carriers near the
interface.
