Electric field controlled domain wall dynamics and magnetic easy axis switching in liquid gated CoFeB/MgO films

We present reversible electric (E) field driven switching of the magnetic easy axis in CoFeB/MgO/HfO2 heterostructures from perpendicular to in-plane using an ionic liquid gate. The modification of magnetic anisotropy reaches 0.108 mJ/m2 in a gate voltage range between −3 V and 3.5 V with an efficiency of 82 fJ (V m)–1. The influence of the E-field induced anisotropy changes on domain nucleation and propagation of magnetic domain walls has also been studied in the perpendicular anisotropy state. A significant modulation of the domain wall velocity is observed in both the creep and depinning regimes of domain wall motion consistent with the E-field induced anisotropy variation. In addition, we demonstrate voltage controlled magnetization switching under a constant magnetic field and voltage control of domain wall pinning.