In a breakthrough achievement, MIT scientists have used light to create a unique magnetic state in a material. By applying lasers, they have successfully transformed an antiferromagnetic material into an entirely new magnetic state. The discovery has the potential to revolutionize next-generation memory and data storage technologies, paving the way for chips that are far more advanced than today's standards.

Details of the breakthrough

The research team, led by physics professor Nuh Gedik, focused on a material called FePS₃, an antiferromagnet that transitions to a nonmagnetic state at around -247°F. They hypothesized that precisely exciting the vibrations of FePS₃ atoms with lasers could disrupt their typical antiferromagnetic arrangement and induce a new magnetic state.

In conventional magnets (ferromagnets), all atomic spins align in the same direction, making magnetic fields easy to control. Antiferromagnets, by contrast, have a more complex pattern of up-and-down, up-and-down spins that cancel each other out, resulting in a net magnetization of zero. While this property makes antiferromagnets highly resistant to stray magnetic fields—an advantage for secure data storage—it also creates a challenge for intentionally switching them between "0" and "1" states for computing.

Gedik's innovative laser-driven approach aims to overcome this obstacle, potentially unlocking antiferromagnets for future high-performance memory and computing technologies.

The team's innovative approach is to cool a sample of FePS₃ to below its transition temperature and then bombard it with carefully tuned terahertz laser pulses. These lasers oscillate more than a trillion times per second, perfectly matching the natural vibration frequency of the material's atoms.

Surprisingly, the researchers found that these pulses push the material into a completely new magnetization state, and that this state persists for several milliseconds after the laser pulse ends.

Although a few milliseconds may seem fleeting, in the quantum world, it is actually an eternity compared to previous attempts, as Gedik emphasizes.

Going forward, the researchers aim to improve and further understand these induced magnetic phases. The ultimate goal is to exploit antiferromagnets in the next generation of data storage and processing hardware. Their strong magnetic domains are immune to stray magnetic noise, allowing for denser and more energy-efficient memory and logic chips than today's technology.

However, significant engineering challenges remain before antiferromagnetic computers can become a reality. The team is optimistic that this can happen, and their groundbreaking findings, published in the journal Nature, represent a key step towards that vision.

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