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arXiv · 2110.11483

Angular harmonic Hall voltage and magnetoresistance measurements of Pt/FeCoB and Pt-Ti/FeCoB bilayers for spin Hall conductivity determination

Witold Skowroński·Krzysztof Grochot·Piotr Rzeszut·Stanisław Łazarski·Grzegorz Gajoch·Cezary Worek·Jarosław Kanak·Tomasz Stobiecki·Jürgen Langer·Berthold Ocker·Mehran Vafaee
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Abstract

Materials with significant spin-orbit coupling enable efficient spin-to-charge interconversion, which can be utilized in novel spin electronic devices. A number of elements, mainly heavy-metals (HM) have been identified to produce a sizable spin current ($j_\mathrm{s}$), while supplied with a charge current ($j$), detected mainly in the neighbouring ferromagnetic (FM) layer. Apart from the spin Hall angle $\theta_\mathrm{SH}$ = $j_\mathrm{s}$/$j$, spin Hall conductivity ($\sigma_\mathrm{SH}$) is an important parameter, which takes also the resistivity of the material into account. In this work, we present a measurement protocol of the HM/FM bilayers, which enables for a precise $\sigma_\mathrm{SH}$ determination. Static transport measurements, including resistivity and magnetization measurements are accompanied by the angular harmonic Hall voltage analysis in a dedicated low-noise rotating probe station. Dynamic characterization includes effective magnetization and magnetization damping measurement, which enable HM/FM interface absorption calculation. We validate the measurement protocol in Pt and Pt-Ti underlayers in contact with FeCoB and present the $\sigma_\mathrm{SH}$ of up to 3.3$\times$10$^5$ S/m, which exceeds the values typically measured in other HM, such as W or Ta.

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Witold Skowroński, Krzysztof Grochot, Piotr Rzeszut, Stanisław Łazarski, Grzegorz Gajoch, Cezary Worek, Jarosław Kanak, Tomasz Stobiecki, Jürgen Langer, Berthold Ocker, Mehran Vafaee. 2021-10-21. Angular harmonic Hall voltage and magnetoresistance measurements of Pt/FeCoB and Pt-Ti/FeCoB bilayers for spin Hall conductivity determination. https://doi.org/10.1109/ted.2021.3122999

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