Field-free switching enabled by interplay of spin-orbit torque and interlayer Dzyaloshinskii-Moriya interaction

Realizing field-free perpendicular magnetization switching driven by spin-orbit torque (SOT) in a system compatible with sophisticated technology of magnetic random-access memory (MRAM) is challenging and crucial for the development of SOT-MRAM. Here, making use of an interlayer Dzyaloshinsky-Moriya interaction(iDMI) effect in the classic Pt/[Co/Pt] n /Pt multilayers and Pt/Co/Pt/Ir/Pt/Co/Pt synthetic antiferromagnetic (SAF) structures with perpendicular magnetic anisotropy (PMA), we achieved the desired field-free switching in a maximized degree as current applied colinear with a D vector. In contrast, the switching was fully disabled by an orthogonal configuration between the current and the D vector. These rules reproducible theoretically define a new SOT symmetry breaking law for the chiral magnets with the iDMI under zero applied field. Moreover, our work can also broaden usage of the classic [Pt/Co] n multilayer system and the SAF structures from a passive pinned layer in a spin-transfer torque MRAM to an active data-storage layer in a perpendicular SOT-MRAM and expedite the development of the practical and efficient SOT devices.