Magnetic excitations can travel through certain materials. In analogy to the electron, themagnons could transport information much more easily than electrical conductors. An international research team has made an important discovery on the road to such components, which could be highly energy-efficient and considerably smaller.
Most electronic components are based on the transport and control of electrical charges. This technology has a major disadvantage because of the heat generated by the electric currents. The amount of electronic components used worldwide leads to a huge loss of energy.
Spin waves do not produce as much waste heat as conventional waves do. The components could be much smaller. Magnetic spin waves can be used to transport information, and scientists around the world are looking for materials that can do that.
An international research consortium has taken an important step in the search. Their observations of spin waves on circular paths in magnetic materials could represent a breakthrough for quantum technologies that use waves to transport information.
Magnetic waves arePropagation of magnetic waves in materials
When you throw a stone into the water, the water will leave its equilibrium position. A circular wave spreads out as they start to oscillate. The magnetic moments in some materials can be oscillated. The magnetic moment does a gyroscopic motion with respect to its rest position. The wave propagation is caused by the precession of one moment.
Control of properties such as wavelength or direction is important for applications using magnetic waves. Magnetic waves generally travel in a straight line in conventional ferromagnets.
The propagation of such waves is different in a new class of magnetic materials. The magnetic order was discovered fifteen years ago by a team led by Christian Pfleiderer.
Skyrmions are named after the British nuclear physicist Tony Skyrme because of their non-trivial topological properties.
Magnetic waves are propagation on a circular path.
The study of magnetic materials can be done with neutrons since they carry a magnetic moment. Magnetic fields are similar to a compass needle. The only technique that could detect spin waves on a circular path was Neutron scattering.
The propagation of magnetic waves on a circular path is proven by the team from theInstitut Laue Langevin in France.
The direction of neighboring magnetic moments and the direction of the axis about which the precessional motion occurs are constant. The direction of propagation changes continuously when the precessional motion moves from one magnetic moment to the next. The direction of the propagation of the spin waves depends on the strength of the magnetic moment.
There is a method for determining the circular orbits.
The theoretical description of spin waves in skyrmions and their correlation to neutrons was developed some time ago by Markus Garst of theKIT.
Their energy is quantized at very low temperatures. Predicted almost a hundred years ago by Russian physicist Lev Landau, this phenomenon is called Landau quantization. The influence of the skyrmions on the spin waves can be seen as a magnetic field. The interplay of the spin waves with the skyrmion structure is very simple and can be described like the motion of electrons in a magnetic field.
The propagation of spin waves shows a quantization of the circular orbits. The spin wave's characteristic energy is quantized, which opens the door to completely new applications. There is a subtle twist to the circular orbit. The twist can only be removed by cutting and connecting the strip. The spin wave motion is stable because of this.
International cooperation is successful.
The determination of spin waves in skyrmion lattices required both a combination of world-leading neutron spectrometers and a massive advancement of the software to interpret the data.
The research team used instruments of theInstitut Laue-Langevin in France, the spallation source SINQ at the Swiss Paul Scherrer Institute, the UK's ISIS neutron and muon source, and the Research Neutron Source Heim Maier-Leibnitz. Theory and data analysis was done at the U.S. Los Alamos National Laboratory.
After countless experiments at world-leading spectrometers and the clarification of major experimental and theoretical challenges during my time at Los Alamos, it is great to see that the tiny detection of Landau quant is possible.
The motion of spin waves on circular orbits, which are quantized to boot, is a breakthrough not only from the perspective of fundamental research. Christian Pfleiderer, managing director of the newly founded Center for Quantum Engineering at TUM, emphasizes that the motion of spin waves on circular orbits opens up a new perspective for realizing.
More information: T. Weber et al, Topological magnon band structure of emergent Landau levels in a skyrmion lattice, Science (2022). DOI: 10.1126/science.abe4441 Journal information: Science Citation: Magnetic excitations could provide information transfer without heat loss (2022, March 3) retrieved 3 March 2022 from https://phys.org/news/2022-03-magnetic-loss.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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