Coherent Picture on the Pure Spin Transport between Ag/Bi and Ferromagnets

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Pure spin transport at interfaces is crucial for spintronics.
• The inverse Rashba-Edelstein effect (IREE) is a key mechanism for spin-charge conversion.
• Previous studies on Ag/Bi interfaces reported conflicting results regarding spin transport mechanisms.

Purpose of the Study:

• To resolve the debate surrounding spin transport at Ag/Bi and ferromagnet interfaces.
• To elucidate the dominant spin transport mechanism, distinguishing between IREE and inverse spin Hall effect.
• To investigate the tunability of spin transport properties at Ag/Bi-ferromagnetic metal interfaces.

Main Methods:

• Combined experimental investigations with first-principles calculations.
• Fabrication and characterization of Ag/Bi interfaces with ferromagnetic metals and insulators.
• Analysis of spin-polarized current and voltage signals to identify spin transport mechanisms.

Main Results:

• Demonstrated a strong IREE at the Ag/Bi interface when coupled with a ferromagnetic metal (FM), not a ferromagnetic insulator.
• Contradicted prior claims of IREE at Ag/Bi interfaces or dominant inverse spin Hall effect.
• Achieved over an order of magnitude modulation of the IREE signal by varying the Ag/Bi-FM interface.

Conclusions:

• The study provides a coherent understanding of pure spin transport at Ag/Bi-FM interfaces.
• The demonstrated strong and tunable IREE highlights the potential of Ag/Bi-FM systems for spintronic applications.
• This work opens new avenues for discovering and designing efficient spintronics materials.