  In the quest to develop spintronic logic, it was discovered that
magnetoelectric switching results in lower energy and shorter switching time
than other mechanisms. Magnetoelectric (ME) field due to exchange bias at the
interface with a multi-ferroic (such as BiFeO3) is well suited for 180 degree
switching of magnetization. The ME field is determined by the direction of
canted magnetization in BiFeO3 which can point at an angle to the plane, to
which voltage is applied. Dependence of switching time and the threshold of ME
field on its angles was determined by micromagnetic simulations. Switching
occurs by formation of a domain wall on the side of the nanomagnet on top of
BFO and its propagation to the rest of the magnet. For in-plane magnetization,
switching occurs over a wide range of angles and at all magnitudes of ME field
above threshold. For out-of-plane magnetization failure occurs (with an
exception of a narrow range of angles and magnitudes of ME field) due to the
domain wall reflecting from the opposite end of the nanomagnet.
