Detection of the dc inverse spin Hall effect due to spin pumping in a novel meander-stripline geometry

TL;DR

This paper introduces a novel meander-stripline geometry that isolates the inverse spin Hall effect (iSHE) signal from rectification artifacts in ferromagnet/normal-metal bilayers, enabling more accurate measurements across various materials.

Contribution

The study presents a new geometry that eliminates spurious rectification voltages, allowing precise quantification of the dc iSHE due to spin pumping in multilayers and single films.

Findings

Spurious rectification voltages are suppressed in the new geometry.

Quantitative iSHE measurements are achieved in Permalloy/NM multilayers.

A small iSHE voltage is observed in single CoFe thin films.

Abstract

The dc voltage obtained from the inverse spin Hall effect (iSHE) due to spin pumping in ferromagnet/normal-metal (NM) bilayers can be unintentionally superimposed with magnetoresistive rectification of ac charge currents in the ferromagnetic layer. We introduce a geometry in which these spurious rectification voltages vanish while the iSHE voltage is maximized. In this geometry, a quantitative study of the dc iSHE is performed in a broad frequency range for Permalloy/NM multilayers with NM={Pt, Ta, Cu/Au, Cu/Pt}. The experimentally recorded voltages can be fully ascribed to the iSHE due to spin pumping. Furthermore we measure a small iSHE voltage in single CoFe thin films.