New Magnetic State Using Light

Researchers at MIT have discovered a way to control magnetic materials, using terahertz light to create a stable, long-lasting magnetic state in antiferromagnetic materials that could transform data storage and memory technologies, offering faster, more efficient, and durable solutions for next-generation electronics.

MIT physicists have unlocked a method to manipulate magnetic materials, creating a long-lasting magnetic state in an antiferromagnetic material using light. The study details how a terahertz laser—a light source oscillating trillions of times per second—was used to stimulate atomic vibrations, shifting the balance of atomic spins and achieving a new magnetic state.

Antiferromagnets, unlike traditional magnets where atomic spins align uniformly, have alternating spins that cancel each other, resulting in zero net magnetization. This property makes them resistant to external magnetic fields but also difficult to control. The MIT team’s success in switching antiferromagnetic states opens up possibilities for advanced data storage and memory technologies. Future memory chips could harness this technology to write data as stable spin configurations, impervious to stray magnetic fields, enhancing durability and efficiency.

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Led by Professor Nuh Gedik, the research team employed a terahertz light pulse tuned to the atomic vibrations of FePS3, an antiferromagnetic material. At temperatures below 118 K (-247°F), they directed terahertz pulses at the material, exciting its atomic vibrations and indirectly influencing spin interactions. This “shaking” knocked the atomic spins out of balance, creating a new magnetic state.

The process was confirmed through infrared laser tests that revealed changes in the material’s magnetic properties. This new state persisted for milliseconds—thousands of times longer than typical light-induced transitions, which last mere picoseconds. This extended window allows researchers to explore the material’s properties and refine techniques for controlling antiferromagnets. Such advancements could revolutionize memory chips by offering compact, energy-efficient solutions with unparalleled stability.