  The control of magnetization via the application of an electric field, known
as magnetoelectric coupling, is among the most fascinating and active research
areas today. In addition to fundamental scientific interest, magnetoelectric
effects may lead to new device concepts for data storage and processing. There
are several known mechanisms for magnetoelectric coupling that include
intrinsic effects in single-phase materials, strain induced coupling in
two-phase composites, and electronically-driven effects at interfaces. Here we
explore a different type of magnetoelectric effect at a
ferromagnetic-ferroelectric interface: magnetic reconstruction induced by
switching of electric polarization. We demonstrate this effect using
first-principles calculations of a La1-xAxMnO3/BaTiO3 (001) interface, where A
is a divalent cation. By choosing the doping level x to be near a transition
between magnetic phases we show that the reversal of the ferroelectric
polarization of BaTiO3 leads to a change in the magnetic order at the interface
from ferromagnetic to antiferromagnetic. This predicted electrically-induced
magnetic reconstruction at the interface represents a substantial interfacial
magnetoelectric effect.
