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 Néel 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.