Spin Wave Radiation by a Topological Charge Dipole.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Spin waves (SWs) are promising for low-power spintronic and magnonic logic devices.
• Controlled emission and propagation of SWs in magnetic materials present significant challenges.
• Existing methods lack precise control over SW generation and directionality.

Purpose of the Study:

• To investigate skyrmion-antiskyrmion bilayers as efficient sub-100 nm SW emitters.
• To demonstrate the role of topological charge dipoles in SW generation.
• To explore the potential of these bilayers as SW antennas for controlled signal radiation.

Main Methods:

• Theoretical proposal of skyrmion-antiskyrmion bilayers as SW emitters.
• Excitation of bilayers using in-plane alternating current (ac) magnetic fields.
• Analysis of the radiation patterns and spatial profiles of emitted SWs.

Main Results:

• Skyrmion-antiskyrmion bilayers act as efficient SW emitters with dipole signatures.
• Emitted SWs exhibit a preferred radiation direction, functioning as SW antennas.
• Bilayers with same topological charge produce spiral and antispiral SW patterns.
• SW characteristics (amplitude, direction, wavelength) are controllable via source topology.

Conclusions:

• Skyrmion-antiskyrmion bilayers offer a novel route for controlled SW emission.
• The topological nature of the bilayer dictates SW properties, enabling precise manipulation.
• This approach advances the development of advanced spintronic and magnonic devices.