Field-free spin–orbit torque switching enabled by controllable domain wall chirality

Driven by the exponential growth of artificial intelligence, the internet of things, and cloud computing, the surge in global data generation has intensified the demand for memory technologies that offer high density, ultrafast operation, and low power consumption. While conventional static random-access memory—widely employed as cache memory—faces limitations due to high static power and poor scalability, spin–orbit torque magnetic random-access memory (SOT-MRAM) presents a compelling alternative with its non-volatility, picosecond-scale switching, and ultrahigh endurance, positioning it as a promising candidate for embedded cache applications. However, its widespread adoption has been impeded by the need for an external magnetic field to achieve deterministic magnetization switching. Here, we introduce a field-free switching mechanism via controlled magnetic domain wall (DW) chirality due to time-reversal symmetry breaking. We establish a tensile-strain-mediated easy-cone magnetic anisotropy system in a W/CoFeB/MgO heterostructure, where we control the DW chirality by a one-time magnetic initialization process. The controllable DW chirality breaks time-reversal symmetry and induces deterministic magnetization switching by spin–orbit torque without external field. Fabricated on an industry-standard 300 mm wafer platform, our sub-100 nm SOT-magnetic tunnel junctions achieve near 100% field-free switching probability, a thermal stability factor of 64, endurance exceeding 10¹² cycles, a tunnel magnetoresistance of 116%, and robust thermal stability up to 350 °C. This work establishes a chirality-mediated switching paradigm that integrates materials innovation with scalable manufacturing, providing a viable pathway toward high-performance, energy-efficient SOT-MRAM for the data-centric era.