Physicists generate new nanoscale spin waves

Physicists generate new nanoscale spin waves

Illustration of the experiment. Credit: Dreyer et al, Nature Communications (CC-BY-SA 4.0)

Strong alternating magnetic fields can be used to generate a new type of spin wave that was previously only theoretically predicted. This was first achieved by a team of physicists at the Martin Luther University Halle-Wittenberg (MLU). They report on their work in Communication of nature and provides the first microscopic images of these spin waves.

The basic idea of ​​spintronics is to use a special property of electrons – spin – for various electronic applications such as data and information technology. Spin is the intrinsic angular momentum of electrons that produces a magnetic moment. The coupling of these magnetic moments creates the magnetism that could eventually be used in information processing. When these coupled magnetic moments are locally excited by a magnetic field pulse, these dynamics can propagate as waves throughout the material. These are called spin waves or magnons.

A special type of these waves is at the heart of the Halle physicists’ work. Normally, nonlinear excitation of magnons produces whole numbers of the output frequency—1,000 megahertz becomes 2,000 or 3,000, for example.

“So far, it has only been theoretically predicted that nonlinear processes can generate spin waves at higher than half-integer multiples of the excitation frequency,” explains Professor Georg Woltersdorf from the Institute of Physics at MLU. The team has now been able to show experimentally what conditions are needed to generate these waves and control their phase. Phase is the state of oscillation of a wave at a given point and time. “We are the first to confirm these excitations in experiments, and we have even been able to map them,” says Woltersdorf.

According to the physicist, the waves can be generated in two stable phase states, which means that this discovery could be used in data processing applications, since computers, for example, also use a binary system.

Spintronics: How an atom-thin insulator helps transport spins

More information:
Rouven Dreyer et al, Imaging and Phase Locking of Nonlinear Spin Waves, Communication of nature (2022). DOI: 10.1038/s41467-022-32224-0

Provided by Martin-Luther-Universität Halle-Wittenberg

Citation: Physicists generate new nanoscale spin waves (2022, September 15) Retrieved September 21, 2022, from

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