Ultrathin tungsten films enabling enhanced electrical response to spin currents

Morales-Aragonés, José Ignacio ; Groen, Inge ; Hueso, Luis E ; Casanova, Fèlix ; Pardo, José Ángel (Universidad de Zaragoza) ; Sánchez-Azqueta, Carlos (Universidad de Zaragoza) ; De Teresa, José María ; Sangiao, Soraya (Universidad de Zaragoza)

Resumen: 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 σSH = −1.14(6) × 105 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 λsd = 4.3(5) × 10−15Ωm2/ρW, where the W resistivity ρW is strongly dependent on thickness. Structural characterization, together with roomtemperature 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.

Idioma: Inglés

DOI: 10.1088/1361-6463/ae5dde

Año: 2026

Publicado en: Journal of physics. D, Applied physics 59, 17 (2026), 175301 [13 pp.]
ISSN: 0022-3727

Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2023-146451OB-I00
Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2023-150244OB-I00
Financiación: info:eu-repo/grantAgreement/ES/DGA/E13-23R
Financiación: info:eu-repo/grantAgreement/ES/DGA/E29-24
Financiación: info:eu-repo/grantAgreement/ES/DGA/T33-24
Financiación: info:eu-repo/grantAgreement/ES/MCIU/PID2020-112914RB-I00
Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2021-122511OB-I00
Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2024-155708OB-I00

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Aplicada (Dpto. Física Aplicada)
Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)
Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)