Control of the Magnetic Anisotropy in Multi-Repeat Pt/Co/Al Heterostructures Using Magneto-Ionic Gating

Controlling magnetic properties through the application of an electric field is a significant challenge in modern nanomagnetism. In this study, we investigate the magnetoionic control of magnetic anisotropy in the topmost Co layer in Ta/Pt/[Co/Al/Pt](n)/Co/Al/AlOx multilayer stacks comprising n + 1 Co layers and its impact on the magnetic properties of the multilayers. We demonstrate that the perpendicular magnetic anisotropy can be reversibly quenched through gate -driven oxidation of the intermediary Al layer between Co and AlOx, enabling dynamic control of the magnetic layers contributing to the out -of -plane remanence-varying between n and n + 1. For multilayer configurations with n = 2 and n = 4, we observe reversible and nonvolatile additions of 1/3 and 1/5, respectively, to the anomalous Hall -effect amplitude based on the applied gate voltage. Magnetic imaging reveals that the gate -induced spin -reorientation transition occurs through the propagation of a single 90 magnetic domain wall separating the perpendicular and in -plane anisotropy states. In the five -repetition multilayer, the modification leads to a doubling of the period of the magnetic domains at remanence. These results demonstrate that the magnetoionic control of the anisotropy of a single magnetic layer can be used to control the magnetic properties of coupled multilayer systems, extending beyond the gating effects on a single magnetic layer.