Interface effects at a half-metal/ferroelectric junction

Magnetoelectric effects are investigated ab initio at the interface between half-metallic and ferroelectric prototypes: Heusler Co(2)MnSi and perovskite BaTiO(3). For the Co-termination ferroelectricity develops in BaTiO(3) down to nanometer thicknesses, whereas for the MnSi termination a paraelectric and a ferroelectric state energetically compete, calling for a full experimental control over the junction atomic configuration whenever a ferroelectric barrier is needed. Switch of the electric polarization largely affects magnetism in Co(2)MnSi, with magnetoelectric coupling due to electronic hybridization at the MnSi termination and to the structural effects at the Co-termination. Half metallicity is lost at the interface, but recovered already in the subsurface layer. (c) 2007 American Institute of Physics.