- Light can rapidly change magnetic behavior, suggesting faster data storage methods
- Researchers controlled magnets thinner than a hair without extreme cooling or extreme conditions
- Laser pulses changed the behavior of the magnet by up to forty percent at room temperature
Modern digital life depends to a large extent on how efficiently information can be stored and processed.
From hard drives to new computer systems, magnetism remains central to these technologies because it controls how bits are written, moved, and preserved.
Engineers have long searched for ways to adjust magnetic behavior quickly and precisely without relying on heat-heavy electrical currents.
Moves 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 previous experiments showed that laser pulses could affect magnetic excitations, but only in bulk materials, at very low temperatures or through specialized mid-infrared laser systems.
These limitations make it difficult to envisage integration into everyday hardware, as such conditions collide with scalable manufacturing and practical device operation.
Against this background, German, Swiss and Italian researchers recently reported experimental results indicating that such limitations may not be inevitable.
Their study, published in Nature communicationinvestigates whether magnetic excitations can be optically tuned 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 plane, creating a well-defined magnetic state prior to excitation.
Using femtosecond pump-probe techniques, the researchers monitored how the magnetization responded after short pulses of visible light hit the material.
Because the photon energy exceeds the material’s band gap, laser-induced heating rather than selective resonant excitation dominates.
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 increased.
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 short flashes of light to dial up or down magnetic behavior in a material thinner than a human hair while operating at room temperature.
This suggests a future where magnetic components in business computers and storage devices can be adjusted faster and with less energy.
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