Highly efficient spin-orbit torque switching in Pt/Li_0.5Al_1.0Fe_1.5O₄ bilayers

Spin-wave-based electronics promise fast electrical switching of magnetization but require the isotropic excitation of spin waves and minimization of losses associated with spin-charge conversion. In this regard, spin-orbit torque (SOT) has been identified as a key phenomenon that may enable the coherent excitation of spin waves. Previously, we demonstrated the synthesis of the novel spinel oxide insulator Li_0.5Al_1.0Fe_1.5O₄ (LAFO) films on (001) oriented MgGa₂O₄ that possess PMA and a Gilbert damping parameter on the order of 10^-3. In this talk, we demonstrate current induced SOT switching of the magnetization in Pt/LAFO bilayers at current densities as low as 6 x 10⁵ A/cm^2, one of the lowest reported for a PMA ferrimagnetic insulator. Using second harmonic Hall measurements, we elucidate the origin of this low current density by quantifying a high damping-like SOT efficiency of 0.54. This is much larger than the typical value of < 0.1 in other Pt/ferromagnet systems. The combination of PMA, low damping, and efficient SOT switching make LAFO a promising system for future spintronics applications.