Voltage Manipulation of Synthetic Antiferromagnetism in CoFeB/Ta/CoFeB Heterostructure for Spintronic Application

The synthetic antiferromagnets (SAFs) with inserted heavy metal tantalum (Ta) are attracting an increasing interest due to the relatively large spin Hall angles, resulting in a much lower driven current for low-power consumption, and the conduciveness to high magnetoresistance, showing more suitability for an application. Here, stable and reversible switching behavior is experimentally realized between antiferromagnetic (AFM) coupling and ferromagnetic (FM) coupling in Co₄₀Fe₄₀B₂₀/Ta/Co₄₀Fe₄₀B₂₀/(011) Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) multiferroic heterostructures after applying an external voltage, proved by vibrating sample magnetometer (VSM) and ferromagnetic resonance (FMR) measurements. The indirect interaction shows no periodical oscillation with the layer thicknesses variation of FM layer or nonmagnetic (NM) layer experimentally, which is consistent with the previous reports in theoretical calculation. This work is instructive and guiding for a better understanding of SAFs and realizing the next generation of AFM spintronic devices.