Antiferromagnet-mediated spin–orbit torque induced magnetization switching in perpendicularly magnetized L1-MnGa

Abstract

Current-induced magnetization switching plays an essential role in spintronic devices exhibiting nonvolatility, high-speed processing, and low-power consumption. Here, we report on the spin–orbit torque-induced magnetization switching in perpendicularly magnetized L1₀-MnGa/FeMn/Pt trilayers grown by molecular-beam epitaxy. An antiferromagnetic FeMn layer is inserted between the spin current generating Pt layer and spin absorbing MnGa layer. Due to the exchange bias effect, the trilayers show field-free spin–orbit torque switching. Overall, the spin transmission efficiency decreases monotonically as the FeMn thickness increases. It is found that the spin current can be transmitted through an 8 nm-thick FeMn layer as evidenced by partial switching of the L1₀-MnGa. The damping-like spin–orbit torque efficiency shows a peak value at t_FeMn = 1.5 nm due to the enhanced interfacial spin transparency and crystalline quality of the FeMn. These results help demonstrate the efficacy of emerging spintronic devices containing antiferromagnetic elements.