Electric Field Modulation of Interlayer Coupling via Piezostrain in a Synthetic Antiferromagnet

Controlling the interlayer exchange coupling (IEC) in synthetic antiferromagnets (SAFs) using an electric field is a promising approach for developing energy-efficient spintronic devices, as it enables magnetization switching without electrical current. In this study, the modulation of the IEC through electric field-induced strain in a Co/Ru/Co SAF on a Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) multiferroic heterostructure is demonstrated. It is found that both the IEC and the uniaxial magnetic anisotropy energy are modulated by applying an electric field to the Co/Ru/Co/PMN-PT structure. This modulation is evident from the behavior of the minor hysteresis loops observed in our experiments and micromagnetic simulations. Additionally, it is clarified that the in-plane piezoelectric strain transferred from the PMN-PT to the Co/Ru/Co SAF layer enhances the strength of the antiferromagnetic IEC. Notably, the efficiency of this enhancement due to piezoelectric strain is strongly correlated with the thickness of the Ru spacer, a finding that aligns with our first-principles calculations. Controlling the IEC via the piezoelectric strain transfer effect using an electric field enables the manipulation of antiferromagnetic order with extremely low energy consumption, offering significant potential for energy-efficient spintronic memory devices.