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.

The modulation of perpendicular magnetic anisotropy and spin–orbit toque in Pt/Co/Pt multilayers with interfacial decoration by insertion of a Bi layer

“…Considerable efforts have been made to enhance the SHA of Pt though impuriy scattering by alloying Pt with impurity metals, for example, alloying Pt with Hf, Al, or Au [17,18]. Recently, PtBi 2 alloy and Pt doped with low-concentration Bi have been demonstrated to exhibit larger SHA [19,20].…”