High Temperature Ferromagnetism in a GdAg2 Monolayer

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Advanced materials with ferromagnetism, interfacial stability, and tunability are crucial for novel magnetoelectronic phenomena in heterostructures.
• Rare-earth/noble metal surface alloys offer potential for spintronic applications.

Purpose of the Study:

• To investigate the ferromagnetic properties of the GdAg2 monolayer alloy.
• To understand the mechanism behind its high Curie temperature and interfacial properties.

Main Methods:

• Experimental techniques: X-ray absorption, Kerr effect, angle-resolved photoemission.
• Theoretical calculations: ab initio methods.
• Comparative study of GdAg2 and GdAu2 monolayers.

Main Results:

• GdAg2 monolayer exhibits ferromagnetism with a significantly enhanced Curie temperature (85 K) compared to GdAu2 (19 K).
• Magnetic coupling is mediated by noble metal-Gd hybrid s,p-d bands, not direct Gd-Gd exchange.
• Surface confinement and electron occupation of hybrid bands enhance the Curie temperature in GdAg2.
• GdAg2 demonstrates chemical stability when interfaced with organic semiconductors or magnetic nanodots.

Conclusions:

• GdAg2 monolayer is a promising material for magnetoelectronics due to its high Curie temperature and stability.
• The findings highlight the importance of hybrid s,p-d bands in mediating magnetism in rare-earth/noble metal alloys.
• Encourages further research into rare-earth/noble metal surface alloys for spintronic applications.