Spin-Selective Interface Engineering in Oxide-Ferromagnetic Junctions via Atomic-Scale Oxygen Control

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Atomic-scale control of oxide-ferromagnet interfaces is vital for spintronic devices.
• Interfacial oxygen in MgO/Fe(100) is difficult to control and verify, impacting device performance.

Purpose of the Study:

• To deterministically tune the MgO/Fe(100) interface by controlling oxygen content.
• To establish a calibrated growth protocol for reproducible interface fabrication.
• To investigate the impact of interfacial oxygen on spintronic properties.

Main Methods:

• Reactive growth under controlled oxygen exposure.
• Momentum-resolved photoemission spectroscopy.
• Complementary spectroscopic methods (e.g., work function measurements).
• Spin-resolved photoemission spectroscopy.

Main Results:

• Successfully tuned MgO/Fe(100) interfaces from oxygen-free to fully oxygen-intercalated states while preserving epitaxy.
• Identified oxygen-dependent k-space fingerprints originating from the buried interface.
• Linked k-space signatures to interfacial chemistry, structure, work function, and an interface resonance.
• Demonstrated post-growth conversion of interface terminations.
• Observed reduced spin contrast at the Fermi level with oxygen intercalation.

Conclusions:

• Developed a calibrated protocol for reproducible preparation and identification of three distinct interface terminations.
• Established MgO/Fe(100) as a benchmark system for optimizing spintronic functionality in oxide/metal junctions.
• Showcased interfacial oxygen as a tunable parameter for spintronic applications.