Electric field modulation of exchange bias at the Co/CoOx interface

We demonstrated the electric field (EF) effect on exchange bias (EB) in a perpendicularly magnetized $\mathrm{Co}/\mathrm{Co}{\mathrm{O}}_{x}$ layered structure. The antiferromagnetic $\mathrm{Co}{\mathrm{O}}_{x}$ layer was formed by naturally oxidizing the Co surface. The modulation of the EB field and the coercivity by gate voltage application through a dielectric layer was clearly observed below the blocking temperature ${T}_{\mathrm{B}}$. The modulation ratio of the EB field exhibited strong temperature dependence, and it increased as the temperature approached ${T}_{\mathrm{B}}$. One possible cause of the EB modulation detailed herein is the modulation of the electronic state at the $\mathrm{Co}/\mathrm{Co}{\mathrm{O}}_{x}$ interface, which is fundamentally different from the case in which multiferroic antiferromagnets are used.