Spin pumping in the Heusler alloy C o2FeAl /Mo S2 heterostructure: Ferromagnetic resonance experiment and theory

Spin pumping from the full Heusler alloy C o₂FeAl film into the transition-metal dichalcogenide Mo S₂ is reported. Plasma-assisted sulfurization of ion-beam sputtered Mo films of different nominal thicknesses is employed to first fabricate large area high-quality Mo S₂ sheets [thicknesses: 1, 2, 3, and 4 monolayers (MLs)] on Si O₂/Si substrates, followed by deposition of C o₂FeAl films with a fixed thickness of 8 nm. The spin pumping is investigated by measuring the changes in the damping constant in the Al(5 nm) capped C o₂FeAl /Mo S₂ bilayers using ferromagnetic resonance spectroscopy. The study demonstrates that even 1 ML of Mo S₂ possesses high enough spin-orbit coupling strength to enhance damping from 5.5 (±0.2 ) ×10^-3 in Al (5 nm ) /C o₂FeAl (8 nm ) to a nearly saturated value of 8.3 (±0.2 ) ×10^-3 in Al (5 nm ) /C o₂FeAl (8 nm ) /Mo S₂(1 ML ) , which is suppressed by inserting a thin Al layer at the C o₂FeAl /Mo S₂ interface. The observed enhancement in damping is in agreement with the results from first-principles calculations based on density functional theory. These results open up a paradigm for designing spintronic devices based on heterostructures comprising a full Heusler alloy and the inherently stable Mo S₂ .