Continuous modulation of charge-spin conversion by electric field in Pt/Co ₂FeSi/Pb(Mg _1/3Nb _2/3)O ₃-Pb _0.7Ti _0.3O ₃ heterostructures

The half-metallic Heusler alloy Co ₂FeSi is an ideal material in spintronic devices due to its higher spin polarization, higher Curie temperature and lower damping parameters. In this work, the dynamic magnetism of Co ₂FeSi is modulated by electric field and it is demonstrated that the charge-spin conversion efficiency ξ is continuous and controllable by the electric field. We further find an extremely high ξ in ferromagnetic/ferroelectric (FM/FE) heterostructures, which could be ascribed to interfacial effect in FM/FE interface. Moreover, we investigate that the charge-spin conversion efficiency varies with the electric field in a butterfly-like behavior, which accords with the S– E curve of Pb(Mg _1/3Nb _2/3)O ₃-Pb _0.7Ti _0.3O ₃(PMN-PT) and could be attributed to strain effect. The modulation of charge-spin conversion efficiency in FM/FE heterostructures via electric field presents a profound potential for next-generation spintronic devices and applications of current-induced magnetization switching.