Reversibly controlled magnetic domains of Co film via electric field driven oxygen migration at nanoscale

Electric field control of perpendicular magnetic anisotropy (PMA) can enable low power consumption for perpendicular magnetic random access memory devices. However, the tuning of PMA by the electric field in ferromagnetic metal thin films is less efficient and limited to the interface due to the screening effect. Alternatively, the magnetoionic effect can control PMA efficiently, which utilizes ion migrations over the surface of the ferromagnetic metal by interfacing it with the charge reservoir of oxygen ions like GdO_x. In this paper, we report the reversibly controlled magnetic domains of PMA Co in the Pt/Co/GdO_x trilayer via the electric field at the nanoscale using conductive atomic force microscopy and magnetic force microscopy (MFM). The magnetic domain phase values determined by MFM decrease and increase when negative and positive bias voltages of magnitude 4 V are applied to the surface of GdO_x, respectively. These results suggest a path toward control of PMA materials at the nanoscale by the electric field for information storage devices.