Antiferromagnetism Emerging in a Ferromagnet with Gain

Area of Science:

• Condensed matter physics
• Spintronics
• Magnonics

Background:

• Ferromagnetic materials with gain or loss are theoretically explored.
• Antiferromagnetic Skyrmions are stable topological quasiparticles that have not been experimentally observed.
• Parity-time (PT) symmetry is a concept relevant to systems with balanced gain and loss.

Purpose of the Study:

• To theoretically establish an equivalence between ferromagnetic systems with gain/loss and antiferromagnetic systems with loss/gain.
• To demonstrate a novel first-order phase transition by tuning the gain-loss parameter.
• To explore the realization and manipulation of antiferromagnetic Skyrmions in ferromagnetic thin films and bilayers.

Main Methods:

• Theoretical mapping of gain/loss in ferromagnets to loss/gain in antiferromagnets.
• Analysis of a chiral ferromagnetic thin film with gain to realize antiferromagnetic Skyrmions.
• Investigation of ferromagnetic bilayers with balanced gain and loss.

Main Results:

• A theoretical equivalence is established: ferromagnet with gain (loss) = antiferromagnet with loss (gain).
• A novel first-order ferromagnet-antiferromagnet phase transition is identified via gain-loss parameter tuning.
• Antiferromagnetic Skyrmions are demonstrated and manipulated in a chiral ferromagnetic thin film with gain.
• Antiferromagnetic Skyrmions are found exclusively in broken parity-time symmetry phases within ferromagnetic bilayers.

Conclusions:

• The study provides a theoretical framework for understanding gain/loss effects in magnetic systems.
• It opens avenues for the experimental realization and manipulation of antiferromagnetic Skyrmions.
• Findings pave the way for advancements in antiferromagnetic spintronics and parity-time symmetric magnonics.