Magnetic antiparticles offer new opportunities for data storage

Magnetic antiparticles offer new opportunities for data storage
Matter and antimatter in the nanoscale magnetic universe: a gas of skyrmions (purple) and antiskyrmions (green) generated from the trochoidal dynamics of a single antiskyrmion seed. // Ill./ ©: Joo-Von Kim via AlphaGalileo

Nanosized magnetic particles known as skyrmions are considered highly promising candidates for new data storage and information technologies.

Physicist have revealed new behaviour involving the antiparticle equivalent of skyrmions (antiskyrmions) in ferromagnetic material, which could allow the particles to be used for new data storage methods and information technologies.

The researchers demonstrated their findings using advanced computer simulations that can accurately model magnetic properties of nanometre-thick materials. The results were obtained by scientists at Uppsala University, Sweden, Kiel University and Johannes Gutenberg University Mainz, Germany, and Université Paris-Saclay, France.

Using electrons for electronics

Moving electrons around in circuits is the basis for creating useful functions in electronics. However, scientists have questioned whether their guiding principles still apply for positrons – the antiparticle of electrons.

Although they are very scarce, basic electrodynamics suggest that everything would essentially function the same way with positive charges as it does with the negative ones of electrons.

However, this question remains open for nanoscale magnetic particles called skyrmions. Skyrmions represent whirls of magnetic moments that extend across a few nanometres, and can be found in magnetic films a few atoms thick.

Skyrmions possess a property called topological charge which plays a similar role to electric charges when their dynamics are concerned. For example, if an applied force causes skyrmions to be deflected toward the left, that same force will lead antiskyrmions, to deflect toward the right. Since the first experimental observations in 2009, skyrmions have been the focus of research as they offer new opportunities for data storage and process information.

Evolution of skyrmion-antiskyrmion pairs

As reported by AlphaGalileo, physicists have shown that a much richer phenomena can occur in nanometer-thick ferromagnets in which both skyrmions and antiskyrmions coexist. By using simulation techniques to compute the magnetic properties in such films, they studied how skyrmions and antiskyrmions respond when electric currents are applied to exert a force on them.

At low currents, the expected behaviour is seen where opposite topological charges are deflected in opposite directions because of the same applied forces. As the current is gradually increased, however, their motion no longer mirrors each other.

While skyrmions continue to travel in straight lines, antiskyrmions begin to undergo curved trajectories, initially as transients and then continuously as the currents are further increased. These results illustrate that opposite topological charges can in fact behave very differently.

However, by increasing the amount of energy transferred to the system from the applied currents, the researchers found that the trochoidal motion can evolve to skyrmion-antiskrymion pairs periodically.

What do the results show?

The results of this research are potentially far-reaching. For future technologies, the study suggests that antiskyrmions could be a ready source of skyrmions, which could be crucial for any applications that use skyrmions for data storage and to transmit information.

The work may also provide hints for solving a bigger mystery on cosmological scales, specifically why there is more matter than antimatter in the observable Universe.

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