Engineering the spin conversion in graphene monolayer epitaxial structures
Résumé
Spin Hall and Rashba–Edelstein effects, which are spin-to-charge conversion phenomena due to spin-orbit coupling (SOC), are attracting
increasing interest as pathways to manage rapidly and at low consumption cost the storage and processing of a large amount of data in
spintronic devices as well as more efficient energy harvesting by spin-caloritronics devices. Materials with large SOC, such as heavy metals
(HMs), are traditionally employed to get large spin-to-charge conversion. More recently, the use of graphene (gr) in proximity with large
SOC layers has been proposed as an efficient and tunable spin transport channel. Here, we explore the role of a graphene monolayer between
Co and a HM and its interfacial spin transport properties by means of thermo-spin measurements. The gr/HM (Pt and Ta) stacks have been
prepared on epitaxial Ir(111)/Co(111) structures grown on sapphire crystals, in which the spin detector (i.e., top HM) and the spin injector
(i.e., Co) are all grown in situ under controlled conditions and present clean and sharp interfaces. We find that a gr monolayer retains the spin
current injected into the HM from the bottom Co layer. This has been observed by detecting a net reduction in the sum of the spin Seebeck
and interfacial contributions due to the presence of gr and independent from the spin Hall angle sign of the HM used.
Invited Paper published as part of the special topic on Emerging Materials for Spin-Charge Interconversion
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Anadon 2021 APL Materials.Engineering the spin conversion in graphene.pdf (7.02 Mo)
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