Enhancement of magnetoelectric effect by combining different interfacial coupling mechanisms

First-principles calculations were used to investigate the interfacial electronic structure and magnetoelectric effect in the Fe/PbTiO3 heterointerface. We demonstrate that the large magnetoelectric effect in this system is determined by the combination of different magnetoelectric coupling mechanisms, i.e., the conjunction of interface bonding mechanism and the electrostatic screening of the spin-polarized carriers. The change of induced magnetic moments on interfacial Ti atoms is due to the variation of interface bonding when the ferroelectric polarization reverses, while the contribution to magnetoelectric coupling from interfacial Fe atoms is determined by the electrostatic screening of spin-polarized carriers. The combination of different interfacial magnetoelectric coupling mechanisms enhances the magnetoelectric coefficient at the Fe/PbTiO3 heterointerface to be several times larger in magnitude than that of individual magnetoelectric coupling mechanism. Our results indicate a new strategy to design multiferroic materials with large magnetoelectric effects. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4719972]