Magneto-ionic control of oxide heterostructures

Ionic transport across a metal/oxide interface offers a highly effective means to tailor the physical properties of the system. In a recent experiment, we have demonstrated a controllable positive exchange bias in GdFe/NiCoO due to redox-driven oxygen migration [1]. We further show that the oxygen migration across the metal/oxide interface can be reversibly controlled by an electric field [2]. Similar magneto-ionic effects are also found in getter/perovskite systems of Gd/LaSrMnO3 [3], Gd/LaSrCoO3 [4] and Gd/YBCO [5]. In more recent experiments we have investigated a series of NiCoO / getter films. Our results show the presence of an interfacial FM layer with large exchange bias, which can be further tailored by an applied voltage bias along with field cooling procedures. These results demonstrate an effective path to tailoring the interfacial characteristics and exchange coupling in metal/oxide heterostructures.