- Researchers demonstrate laser control of room-temperature magnons in thin magnetic materials
- Visible light pulses tune magnetic frequencies without cryogenic conditions
- Nanometer-scale magnets show promise for faster storage and silicon-free computing
Researchers have demonstrated a new way to tune magnetic behavior in extremely thin materials using laser pulses visible at room temperature.
The work focuses on controlling magnons, which are collective spin excitations that play a key role in magnetic devices.
The study, published in Nature Communicationsshows that nanometer-thick magnets can adjust their magnon frequencies both up and down as needed. The material used is only 20 nm thick, making it compatible with dense electronic designs.
Endless possibilities
Magnons are already fundamental to technologies such as hard drives and emerging spin-based computing concepts. Being able to precisely control its frequency has long been considered a requirement for practical devices.
In previous experiments, similar effects were only achieved using mid-infrared lasers, cryogenic temperatures, or bulky materials. Those limitations limited any realistic path to commercial use.
In this new work, the researchers used short visible light laser pulses combined with a modest external magnetic field below 200 mT. This allowed the magnon frequencies to deviate by up to 40 percent from their original value.
Experiments were carried out at room temperature using a bismuth-substituted yttrium iron garnet film grown on a scandium gallium gadolinium garnet (GSGG) substrate. The film’s low damping and strong magneto-optical response were essential.
By adjusting the laser intensity and the magnetic field strength, the team was able to reliably choose whether the magnon frequency increased or decreased.
This level of control comes from the interaction between optical heating, magnetic anisotropy, and the applied field.
The laser pulses act as an ultrafast tuning mechanism rather than a simple heat source. They temporarily change the magnetic stiffness of the material, which directly alters how quickly the magnons oscillate.
Because the effect operates on nanosecond time scales, it opens the door to magnetic logic elements that can be reconfigured almost instantaneously.
These devices could avoid some of the heat and fouling limits faced by silicon electronics.
The combination of room temperature operation, visible light control, and nanoscale thickness means this approach could fit into future computing systems based on storage, signal processing, and spin.
In simple terms, the research could help make everyday technology faster and more efficient, with one of the most obvious uses being data storage.
Hard drives and large cloud servers rely on magnetic materials, and being able to control them more precisely with light could allow data to be written and moved much faster than it is today.
It could also be due to the creation of new types of computer chips that use magnetism instead of electrical current to process information.
These would produce less heat and consume less power, which could lead to quieter laptops, longer battery life and, the holy grail for hyperscalers, cheaper data centers to operate.
Another possible use is hardware that can change what it does on the fly. Instead of building a chip for a single task, light could be used to change its behavior almost instantaneously, allowing one piece of hardware to do different jobs.
Because the effect works at room temperature and in layers thinner than a human hair, it’s also not limited to laboratory experiments, meaning it could eventually be built into phones, computers, and portable storage systems that people already use every day.
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