Giant spin-charge conversion in ultrathin MnPtSb half-Heusler alloy

Half-metallic Heusler alloys are gathering enormous interest as a platform for the next generation of spintronic devices, due to their unique band structure characterized by highly spin-polarized electronic transport at the Fermi level.^[1,2] Here, the broadband ferromagnetic resonance spectroscopy (FMR) is adopted to investigate on the thickness-dependent magnetization dynamic of the MnPtSb(t)/Co(5nm)/Au(5nm) heterostructure down to t= 1nm, demonstrating the possibility to use the MnPtSb alloy as an efficient spin-current generator. Spin pumping-FMR is also employed to determine the spin-to-charge conversion nature in such a system^[3], indicating a predominant contribution from the surface states of the MnPtSb compound. Moreover, when interpreted as arising from the Inverse Edelstein Effect (IEE), the spin-charge conversion efficiency extracted at room temperature for the thinner samples reaches λ_IEE = 3 nm, to our knowledge being the highest room temperature conversion reported so far.

[1]Graf, T. et al. Prog. Solid State Chem. 2011, 39 (1), 1–50 [2]Wen, Z. et al. Sci. Adv. 2019, 5 (12), 1–8 [3]Longo, E. et al. Adv. Funct. Mater. 2021, 2109361