title: Charge-to-Spin Conversion and Spin Diffusion in Bi/Ag Bilayers Observed by Spin-Polarized Positron Beam.
abstract: Charge-to-spin conversion induced by the Rashba-Edelstein effect was directly observed for the first time in samples with no magnetic layer. A spin-polarized positron beam was used to probe the spin polarization of the outermost surface electrons of Bi/Ag/Al2O3 and Ag/Bi/Al2O3 when charge currents were only associated with the Ag layers. An opposite surface spin polarization was found between Bi/Ag/Al2O3 and Ag/Bi/Al2O3 samples with the application of a charge current in the same direction. The surface spin polarizations of both systems decreased exponentially with the outermost layer thickness, suggesting the occurrence of spin diffusion from the Bi/Ag interface to the outermost surfaces. This work provides a new technique to measure spin diffusion length.
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
authors.forename: H J
authors.initials: HJ
authors.lastname: Zhang
authors.affiliation: Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Ibaraki 319-1195, Japan.
authors.forename: B
authors.initials: B
authors.lastname: Gu
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Maekawa
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Fukaya
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kawasuso