Competing exchange interactions in magnetic multilayers

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Magnetic multilayers exhibit tunable interlayer coupling, crucial for spintronic devices.
• Alloying spacer layers offers a method to modify magnetic exchange interactions.

Purpose of the Study:

• Investigate the effect of alloying the vanadium (V) spacer with iron (Fe) on interlayer coupling in Fe/V(100) magnetic multilayers.
• Explore the competition between antiferromagnetic Ruderman-Kittel-Kasuya-Yoshida (RKKY) exchange and direct ferromagnetic exchange.

Main Methods:

• Experimental synthesis and characterization of Fe/V(100) multilayers with varying Fe concentrations in the V spacer.
• Theoretical calculations of exchange coupling and transport properties.
• Measurement of magnetoresistance (MR) as a function of spacer composition and thickness.

Main Results:

• Observed good agreement between theoretical calculations and experimental measurements for exchange coupling and transport properties.
• Demonstrated the creation of competing antiferromagnetic and ferromagnetic exchange interactions by alloying V with Fe.
• Reported a significant reduction in magnetoresistance (approximately 50%) near the transition from antiferromagnetic to ferromagnetic coupling.

Conclusions:

• Alloying the nonmagnetic spacer layer is an effective strategy for tuning interlayer coupling in magnetic multilayers.
• The Fe/V(100) system exhibits a complex interplay of exchange interactions influenced by Fe concentration.
• The observed magnetoresistance reduction highlights the potential for controlling magnetic properties through controlled alloying.