  We study interlayer exchange interaction in magnetic tunnel junctions with
ferroelectric barrier. We focus on the influence of image forces on the voltage
dependence of the interlayer magnetic interaction (magneto-electric effect).
The influence of the image forces is twofold: 1) they significantly enforce
magneto-electric effect occurring due to the surface charges at the interface
between ferroelectric and ferromagnets; 2) in combination with voltage
dependent dielectric constant of the ferroelectric barrier image forces cause
an additional contribution to the magneto-electric effect in magnetic tunnel
junctions. This contribution can exceed the one coming from surface charges. We
compare the interlayer exchange coupling voltage variation with spin transfer
torque effect and show that for half-metallic electrodes the interlayer
exchange coupling variation is dominant and defines the magnetic state and
dynamics of magnetization in the tunnel junction.

Mesoscale and Nanoscale Physics