Ferromagnetic Resonance Spin Pumping and Electrical Spin Injection in Silicon-Based Metal-Oxide-Semiconductor...

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Spin injection is crucial for spintronic devices.
• Ferromagnetic resonance (FMR)-driven spin pumping and electrical spin injection are key mechanisms.
• Understanding spin dynamics at interfaces is vital for device performance.

Purpose of the Study:

• To measure and compare FMR-driven spin pumping and electrical spin injection in a single silicon-based device.
• To investigate the influence of an applied magnetic field in the oblique Hanle geometry on spin accumulation.
• To identify the origins of discrepancies observed between the two spin injection methods.

Main Methods:

• Fabrication of a silicon-based device enabling both FMR-driven spin pumping and three-terminal electrical spin injection.
• Measurement of dc spin accumulation voltage (V_{s}) under varying applied magnetic field orientations.
• Analysis of V_{s} suppression in the oblique Hanle geometry for both injection methods.

Main Results:

• Both FMR-driven spin pumping and electrical spin injection showed suppressed dc spin accumulation voltage (V_{s}) in the oblique Hanle geometry.
• An anomalously strong suppression of V_{s} was observed for FMR-driven spin pumping with increasing out-of-plane field (H_{app}^{z}).
• The observed discrepancy is attributed to the large AC component of the spin current in FMR spin pumping influencing interface spin dynamics.

Conclusions:

• A novel spin injection regime is identified, characterized by the interplay between injector dynamics and interface properties.
• Existing models for FMR-driven spin pumping and electrical spin injection do not fully describe this new regime.
• The findings highlight the importance of considering AC spin current components and interface dynamics in spintronic device design.