Magnetoelectric Switching of Exchange Bias

The perpendicular exchange bias field, ${H}_{mathrm{EB}}$, of the magnetoelectric heterostructure ${mathrm{Cr}}_{2}{mathrm{O}}_{3}(111)/(mathrm{Co}/mathrm{Pt}{)}_{3}$ changes sign after field cooling to below the N’eel temperature of ${mathrm{Cr}}_{2}{mathrm{O}}_{3}$ in either parallel or antiparallel axial magnetic and electric freezing fields. The switching of ${H}_{mathrm{EB}}$ is explained by magnetoelectrically induced antiferromagnetic single domains which extend to the interface, where the direction of their end spins controls the sign of ${H}_{mathrm{EB}}$. Novel applications in magnetoelectronic devices seem possible.