Scientists use flashes of light to control magnetism at room temperature in ultrathin materials once thought impractical | Daily Reports Online
- Light can quickly change magnetic behavior, hinting at faster data storage methods
- Researchers controlled magnets thinner than a hair without extreme cooling or conditions
- Laser pulses altered magnet behavior by up to forty percent at room temperature
Modern digital life depends heavily on how efficiently information can be stored and processed.
From hard disk drives to emerging computing systems, magnetism remains central to these technologies because it governs how bits are written, moved, and retained.
Engineers have long sought ways to adjust magnetic behavior quickly and precisely without relying on heat-heavy electrical currents.
Moving beyond impractical laboratory conditions
Light has often been proposed as an alternative control tool, yet most demonstrations have required extreme conditions that limit real-world relevance.
Many earlier experiments showed that laser pulses could influence magnetic excitations, but only in bulk materials, at very low temperatures, or through specialized mid-infrared laser systems.
These constraints make it difficult to imagine integration into everyday hardware, since such conditions clash with scalable manufacturing and practical device operation.
Against this backdrop, German, Swiss, and Italian researchers recently reported experimental results indicating that such limitations may not be unavoidable.
Their study, published in Nature Communications, explores whether magnetic excitations can be tuned optically in ultrathin materials operating at room temperature and under modest magnetic fields.
The study focuses on a nanometer-thick film of bismuth-substituted yttrium iron garnet grown on a crystalline substrate that introduces strain into the film.
This strain forces the magnetization to orient out of the plane, creating a well-defined magnetic state before excitation.
Using femtosecond pump probe techniques, the researchers monitored how the magnetization responded after short pulses of visible light struck the material.
Because the photon energy exceeds the material band gap, laser-induced heating dominates rather than selective resonant excitation.
The team applied an external magnetic field below 200mT to control the starting magnetic configuration.
Under these conditions, the researchers observed that laser pulses could either raise or lower the frequency of coherent magnons by up to 40%.
Magnons represent collective spin oscillations, and their frequency determines how magnetic information propagates through a material.
The direction of the frequency change depended on both the applied magnetic field and the laser fluence.
Lower fields favored frequency reductions at moderate fluence, while higher fields led to frequency increases as excitation strength rose.
The researchers describe this behavior as on-demand laser-induced frequency tuning of coherent magnons in a nanometer-thick magnet at room temperature.
Modeling and simulations indicate that the effect does not originate from nonlinear interactions caused by large magnon populations.
Instead, it arises from a balance between magnetic anisotropy and the external field, temporarily altered by optical heating.
Put simply, the researchers found a way to use brief flashes of light to dial magnetic behavior up or down in a material thinner than a human hair while it operates at room temperature.
This hints at a future where magnetic components in business computers and storage devices could be adjusted faster and with less energy.
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