Observation of charge-to-spin conversion with giant efficiency at Ni${}_{0.8}$Fe${}_{0.2}$/Bi${}_2$WO${}_6$ interface

Abstract

Magnetization switching using spin-orbit torque offers a promising route to developing non-volatile memory technologies. The prerequisite, however, is the charge-to-spin current conversion, which has been achieved traditionally by harnessing the spin-orbit interaction in heavy metals, topological insulators, and heterointerfaces hosting a high-mobility two-dimensional electron gas. Here, we report the observation of charge-to-spin current conversion at the interface between ferromagnetic Ni${}_{0.8}$Fe${}_{0.2}$ and ferroelectric Bi${}_2$WO${}_6$ thin films. The resulting spin-orbit torque consists of damping-like and field-like components, and the estimated efficiency amounts to about 0.48 $\pm$ 0.02, which translates to 0.96 $\pm$ 0.04 nm${}^{-1}$ in terms of interfacial efficiency. These numbers are comparable to contemporary spintronic materials exhibiting giant spin-orbit torque efficiency. We suggest that the Rashba Edelstein effect underpins the charge-to-spin current conversion on the interface side of Ni${}_{0.8}$Fe${}_{0.2}$. Further, we provide an intuitive explanation for the giant efficiency in terms of the spin-orbit proximity effect, which is enabled by orbital hybridization between W and Ni (Fe) atoms across the interface. Our work highlights that Aurivillius compounds are a potential addition to the emerging transition metal oxide-based spin-orbit materials.

20 pages

References in corpus (3)

• Control of spin-orbit torques by interface engineering in topological insulator heterostructures
• Growth and atomically resolved polarization mapping of ferroelectric $B{i}_{2}W{O}_6$ thin film
• Deterministic influence of substrate-induced oxygen vacancy diffusion on $B{i}_{2}W{O}_6$ thin film growth

Cited by in corpus (1)

• Orbital Hybridization Induces Giant Cubic Rashba Effect at Cu/WO${}_3$ Interface