Deterministic field-free switching of perpendicular magnetization via out-of-plane spin polarization induced by in-plane asymmetry in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>Ta</mml:mi> </mml:math> heterostr

Generating of out-of-plane-polarized spin currents is essential for advancing spintronic applications, yet remains challenging due to the inherent limitations of conventional heavy metals, as well as difficulties in fabricating suitable materials. The authors overcome this challenge through structural design of heavy-metal layers with asymmetry, inducing the desired spin currents and enabling deterministic switching of perpendicular magnetization without applying a magnetic field. The team also identifies the essential structural conditions required for out-of-plane spin polarization within these configurations. This approach offers a feasible pathway toward practical spintronic devices.