Ultrathin tungsten films enabling enhanced electrical response to spin currents
Year: 2026
Type: article
Abstract: The efficient detection of spin currents is crucial for the development of next-generation spintronic devices. Here, we demonstrate that ultrathin W layers, with thicknesses down to 2 nm—equivalent to only four atomic planes—allow for highly efficient spin-to-charge conversion. From spin pumping experiments in YIG/W bilayers, we analyzed the inverse spin Hall effect (SHE) voltage dependence on W thickness and extracted a spin Hall conductivity of σ S H = − 1.14 ( 6 ) × 10 5 Ω − 1 m − 1 , yielding effective spin Hall angles ranging from − 0.27 ( 4 ) to − 0.88 ( 4 ) over the investigated thickness range. Furthermore, assuming the Elliott–Yafet spin scattering mechanism dominates, we estimate a spin diffusion length λ s d = 4.3 ( 5 ) × 10 − 15 Ω m 2 / ρ W , where the W resistivity ρ W is strongly dependent on thickness. Structural characterization, together with room-temperature electrical resistivity measurements and the high spin-to-charge conversion efficiency observed, confirms the stabilization of the β -phase in these ultrathin W layers. We demonstrate that the monotonic increase of the inverse SHE voltage with decreasing W thickness persists down to 2-nm-thick W layer, reflecting the extremely short spin diffusion length. This allows for efficient spin-current detection in W layers below 5 nm, effectively doubling the voltage output at half the thickness. In the thinnest sample, a continuous 2-nm-thick W layer, the generated voltage exceeds 0.5 mV—well within the operating range of conventional electronics. These findings demonstrate not only the feasibility of spin-current detection in ultrathin W, but also its compatibility with conventional electronics. They highlight the strong potential of integrating ultrathin W layers with high-quality YIG films for the development of energy-efficient spintronic devices and sensors.
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
OpenAlex ID: W7153281820