Physics
Brief bursts of light that induce rotation within a material’s atoms may enable the manipulation of a property known as ferroaxiality, potentially paving the way for the creation of stable and efficient memory devices.
Magnet-like materials exhibit internal swirling patterns that can only be controlled using circularly polarized lasers.
Andrew Ostrovsky/iStockphoto/Getty Images
Scientists have successfully controlled a complex material behavior, akin to magnetism, which holds promise for developing advanced hard drives.
Unlike traditional bar magnets that rotate in response to magnetic fields, materials with ferroaxiality defy movement in any known magnetic field. However, researchers led by Zhiyang Zeng from the Max Planck Institute in Germany have discovered a method to manipulate this property using laser technology.
Commonly occurring magnetic materials can be visualized as comprised of numerous tiny bar magnets. Conversely, Zeng proposes that ferroaxial materials should be viewed as collections of dipoles—two opposing electrical charges at a small distance—that whirl around in miniature vortices. His team found that these vortices could be influenced by laser light, contingent upon the light’s swirling properties.
By tuning their lasers to emit circularly polarized light, they were able to direct rotations onto the atoms of a ferroaxial compound composed of rubidium, iron, molybdenum, and oxygen. This action resulted in a shift in the dipoles’ motion.
Team member Michael Först highlights that while researchers have long been aware of the potential of light to control material behaviors—such as converting conductors to insulators—achieving the precise properties necessary for effective control has been a significant technical hurdle.
“This serves as a compelling proof of concept,” remarks Theo Rasing from Radboud University in the Netherlands. He emphasizes that this advancement expands the repertoire of approaches available for creating more effective and stabilized memory devices—hard drives relying on specific patterns of electromagnetic charge for data storage.
Nevertheless, the current experiments necessitate cooling the material to approximately -70°C (-94°F), and the scale of the laser employed is substantial, indicating that further research is essential to advance towards the development of practical applications, according to Först.
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