Magnon dispersion in thin magnetic films

Area of Science:

• Condensed matter physics
• Materials science
• Surface science

Background:

• Magnon dispersion is well-understood in bulk materials.
• Thin films are crucial for technological applications.
• Investigating magnon behavior in thin films is essential for device development.

Purpose of the Study:

• To investigate the magnon dispersion in Mn, Co, and Ni thin films.
• To understand the influence of film thickness on magnon properties.
• To compare thin film behavior with bulk materials.

Main Methods:

• Inelastic tunneling spectroscopy (ITS) was used to measure magnon dispersion.
• Experimental studies were conducted on Mn/Cu3Au(100), and Co and Ni thin films on Cu(100).
• First-principles calculations supported the experimental findings.

Main Results:

• Mn and Co thin films exhibited magnon dispersion similar to bulk materials, with minimal thickness dependence.
• Magnon lifetimes in Mn and Co films showed slight thickness dependence and decreased with increasing magnon energy.
• Ni thin films displayed significant thickness-dependent dispersion, with mode softening in thinner films.
• Magnon lifetimes in Ni films decreased sharply near the Brillouin zone edge due to the Stoner continuum.

Conclusions:

• Magnon dispersion in some thin films (Mn, Co) closely mimics bulk behavior.
• Nickel thin films show unique thickness-dependent magnon properties.
• Understanding these phenomena is key for designing spintronic devices.