All-Electric Low-Power Switching of Perpendicular Magnetization by Low-Crystal-Symmetry Weyl Semimetal NbIrTe₄

The development of energy-efficient spin-orbit torque devices hinges on realizing field-free switching of perpendicular magnetization with minimal power consumption. Here, we demonstrate robust field-free switching of perpendicular magnetization at room temperature, enabled by out-of-plane spins generated in the Weyl semimetal NbIrTe₄. The critical switching current density is 3.6 × 10⁶ A/cm², corresponding to the lowest power consumption reported among intrinsic low-crystal-symmetry materials, 16 times lower than that of WTe₂ and 4 times lower than that of TaIrTe₄. The switching polarity remains stable up to an in-plane magnetic field of 19 mT, confirming the robustness of the field-free operation against magnetic perturbations. Loop-shift measurements and first-principles calculations consistently reveal a large out-of-plane spin Hall conductivity in NbIrTe₄, σ_s,z ≈ 2.61 × 10⁴ (ℏ/2e)(Ω·m)^-1, responsible for the highly efficient and stable magnetization switching. These findings position NbIrTe₄ as a compelling member of the emerging class of low-symmetry materials and offer a promising pathway toward the development of energy-efficient, all-electric spin-orbit torque devices.