Large spin–orbit torque efficiency in PtBi2 film

Abstract

Bulk PtBi2 has attracted much attention for its topological semi-metallic electronic properties and highly promising applications in spintronics. Here, we report large spin–orbit torque (SOT) efficiency in the sputtered PtBi2 alloy with the trigonal-phase. From spin–torque-induced ferromagnetic resonance measurements, the SOT efficiency of 5 nm PtBi2 is estimated to be ∼0.2. Moreover, the spin Hall conductivity of PtBi2 [∼1 × 105 ℏ/2e (Ω m)−1] is comparable to that of topological materials, such PtTe2 and Bi2Te3. The PtBi2 film has much lower resistance than that of Bi-based topological materials, which makes it a useful candidate for application. The results suggest that the PtBi2 alloy is promising for applications in magnetic memory and logic devices driven by SOT.