Controlling magnetic materials

"We now have a full picture", Davide Bossini says. For years, the physicist from the University of Konstanz has studied how to use light to control the collective magnetic oscillations of a material – known as magnons. In the summer of 2025, he was finally able to show how to change the "magnetic DNA" of a material via the interaction between light and magnons. He now demonstrates how the frequency of oscillations can be controlled quasi instantly and on demand by means of a weak magnetic field and intense laser pulses. In this way, he can increase or decrease frequencies by up to 40%. The effect is due to the interaction of the optical excitation, magnetic anisotropy (directional dependence) and the external magnetic field. To get the "whole picture", the method and its effect were studied systematically – both theoretically and experimentally – in collaboration with scientists from the ETH Zurich, the RPTU University Kaiserslautern-Landau and with two Italian research teams at the Polytechnic University of Bari and the University of Messina.

Why is this important? By far the majority of digital data in the cloud is stored magnetically. Control of the frequency of magnetic oscillations means controlling the rate of data writing and transfer. Possible future data technologies will store and transfer data using "spin waves". This is the starting point for Bossini's method that shows how the frequency of such spin waves can be increased or decreased by up to 40%.

Using everyday equipment at room temperature
For Davide Bossini, it is important for his methods to work with everyday equipment and materials. "We don't need a self-developed custom laser", Bossini emphasizes. His experiments were conducted using a commercially available laser system. He also used conventional permanent magnets to generate the magnetic field. "We did everything at room temperature", Bossini adds. By contrast, magnetic materials are often studied at low temperatures of 80 degrees Kelvin (-193.15 degrees Celsius) or colder. "At 20 nanometres thick, the material we used is thus suitable for computer chips", Bossini explains.

The experiments were conducted by the research team led by Davide Bossini at the University of Konstanz. The sample materials were prepared by ETH Zurich, and the theoretical foundations were laid by the Italian partners at the Polytechnic University of Bari and the University of Messina. The research findings were published in Nature Communications.

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You can download a photo here: https://www.uni-konstanz.de/fileadmin/pi/fileserver/2026/magnetische_materialien_beherrschen_1.jpg

Caption: Visible laser pulses and a relatively weak external magnetic field are applied to a sample. This enables the research team to increase or decrease the frequencies of magnons by up to 40%.

Copyright: Volker Wiechert