  The electric manipulation of antiferromagnets has become an area of great
interest recently for zero-stray-field spintronic devices, and for their rich
spin dynamics. Generally, the application of antiferromagnetic media for
information memories and storage requires a heterostructure with a
ferromagnetic layer for readout through the exchange-bias field. In
magnetoelectric and multiferroic antiferromagnets, the exchange coupling exerts
an additional impediment (energy barrier) to magnetization reversal by the
applied magnetoelectric energy. We proposed and verified a method to overcome
this barrier. We controlled the energy required for switching the magnetic
domains in magnetoelectric \cro films by compensating the exchange-coupling
energy from the ferromagnetic layer with the Zeeman energy of a small
volumetric spontaneous magnetization found for the sputtered \cro films. Based
on a simplified phenomenological model of the field-cooling process, the
magnetic and electric fields required for switching could be tuned. As an
example, the switching of antiferromagnetic domains around a zero-threshold
electric field was demonstrated at a magnetic field of 2.6 kOe.
