Ultrafast heating-induced magnetization switching in ferrimagnets

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Binary ferrimagnets, like rare-earth-transition metal alloys (e.g., GdFeCo), exhibit complex magnetic behaviors.
• Light-induced magnetization switching is a key phenomenon for advanced magnetic storage technologies.

Purpose of the Study:

• To theoretically investigate light-induced magnetization switching in binary ferrimagnets.
• To explore the influence of itinerant electron heating and spin dynamics on magnetization reversal.

Main Methods:

• Utilized a theoretical model for a binary ferrimagnet with two magnetic ion species and s-d exchange interaction.
• Employed coupled rate equations to describe the dynamics of localized and itinerant spins.
• Simulated spin dynamics considering electron cooling, exchange scattering, and spin-lattice relaxation.

Main Results:

• Magnetization switching is critically dependent on temperature and the characteristic cooling time of itinerant electrons.
• For longer cooling times, switching occurs below the magnetization compensation temperature (T_K).
• For realistic parameters, the switching temperature range extends from 0 K up to slightly above T_K, shifting higher with decreased cooling time.

Conclusions:

• The study establishes a specific temperature window for achieving light-induced magnetization switching.
• The findings highlight the crucial role of electron spin dynamics and cooling rates in controlling magnetization reversal.
• The theoretical model provides insights applicable to optimizing materials like GdFeCo for spintronic applications.