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Abstract

Identifying materials with an efficient spin-to-charge conversion is crucial for future spintronic applications. The spin Hall effect is a central mechanism as it allows for the interconversion of spin and charge currents. Spintronic material research aims at maximizing its efficiency, quantified by the spin Hall angle θ_SH and the spin-current relaxation length λ_rel. We develop an all-optical method with large sample throughput that allows us to extract θ_SH and λ_rel. Employing terahertz spectroscopy, we characterize magnetic metallic heterostructures involving Pt, W and Cu₈₀Ir₂₀ in terms of their optical and spintronic properties. We furthermore find indications that the interface plays a minor role for the spin-current transmission. Our analytical model is validated by the good agreement with literature DC values. These findings establish terahertz emission spectroscopy as a reliable tool complementing the spintronics workbench.