Spin dynamics and inverse spin Hall effect study in the metallic Pt/NiMn/CoFeB system

Abstract

Generation and manipulation of pure spin current is the governing tool to develop spintronic devices. Spin pumping and the Inverse spin Hall effect (ISHE) are the frontier mechanisms to study the spin current in a system. Ferromagnets (FMs)/heavy metals (HMs) are heavily investigated in such studies. Recently it was found that antiferromagnetic (AFM) materials are a good replacement of HMs in this field. In this context, we have studied the ISHE in Ta (3 nm)/Pt (2.5 nm)/Ni₅₀Mn₅₀ (t nm)/Co₄₀Fe₄₀B₂₀ (3 nm)/Ta (3 nm) samples where the ‘t’ value varies from 0–40 nm. We could observe a finite spin pumping in all the samples. With the introduction of the AFM NiMn layer, the spin pumping voltage reduces to ∼20% in comparison to the reference sample with no NiMn layer. The prominent spin pumping voltage with a 40 nm NiMn layer reveals the finite spin current propagation between Pt and CoFeB. The Gilbert damping (α) decreases by ∼50% with the introduction of NiMn.