Exploring orbital-charge conversion mediated by interfaces with copper through spin-orbital pumping

Abstract

We investigated how different materials affect the orbital-charge conversion in heterostructures with the naturally oxidized cooper capping layer. When we added a thin layer of $CuOx(3nm)$ onto yttrium iron garnet $(YIG)/W$ stacks, we observed a significant reduction in the charge current signal measured by means the spin pumping effect technique. This finding contrasts with the results of a prior study conducted on YIG/Pt/CuOx, which reported the opposite effect. On the other hand, when we added the same $CuOx(3nm)$ layer to $YIG/Ti(4nm)$ structures, there was not much change in the spin pumping signal. This occurred because Ti does not generate much orbital current at the $Ti/CuOx$ interface, unlike Pt, due to its weaker spin-orbit coupling. Interestingly, when we added the $CuOx(3nm)$ layer to $Si{O}_2/Py(5nm)/Pt(4nm)$ structures, the spin pumping signal increased. However, in $Si{O}_2/CuOx(3nm)/Pt(4nm)/Py(5nm)$ structures, the signal decreased. Finally, we delve into a theoretical analysis of the spin (orbital) Hall effect in YIG/Heavy-metal systems. These findings have the potential to advance research in the innovative field of orbitronics and contribute to the development of new technologies based on spin-orbital conversion.

21 pages, 6 figures,

References in corpus (3)

• Giant orbital Hall effect and orbital-to-spin conversion in 3d, 5d, and 4f metallic heterostructures
• Orbital Rashba effect in surface oxidized Cu film
• Y3Fe5O12 Spin Pumping for Quantitative Understanding of Pure Spin Transport and Spin Hall Effect in a Broad Range of Materials

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• Probing orbital currents through inverse orbital Hall and Rashba effects
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• Investigating spin and orbital effects via spin-torque ferromagnetic resonance