Engineering the spin conversion in graphene monolayer epitaxial structures

Alberto Anadón (1) , Adrián Gudín (2) , Rubén Guerrero (1) , Iciar Arnay (1) , Alejandra Guedeja-Marron (1) , Pilar Jiménez-Cavero (3) , Jose Manuel Díez Toledano , Fernando Ajejas (1) , María Varela , Sebastien Petit-Watelot (4) , Irene Lucas , Luis Morellón , Pedro Antonio Algarabel , Manuel Ricardo Ibarra , Rodolfo Miranda , Julio Camarero , J.-C. Rojas-Sánchez (4) , Paolo Perna

1 IMDEA - IMDEA Nanociencia
2 Instituto IMDEA Nanociencia [Madrid]
3 INA - Instituto de Nanociencia de Aragón [Saragoza, España]
4 IJL - Institut Jean Lamour

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

Domaines: Autre [cond-mat.other]; Science des matériaux [cond-mat.mtrl-sci]

Alberto Anadón, Adrián Gudín, Rubén Guerrero, Iciar Arnay, Alejandra Guedeja-Marron, et al.. Engineering the spin conversion in graphene monolayer epitaxial structures. APL Materials, 2021, 9, ⟨10.1063/5.0048612⟩. ⟨hal-03372205⟩