Materials resembling magnets exhibit internal spirals that can solely be controlled with circularly polarized lasers.
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Scientists have successfully regulated the behavior of a previously elusive material, akin to magnetism, which may eventually lead to improved hard drives.
When a bar magnet is introduced to a magnetic field, it rotates due to that influence. However, materials characterized by a property called strong axis remain stationary under all known magnetic fields. Recently, Zeng Zhiyang and his team at the Max Planck Institute for the Structure and Mechanics of Matter in Germany discovered a method to manipulate strong-axis properties using lasers.
A conventional magnetic material is often thought of as a collection of many small bar magnets. Zeng explains that for strong-axis materials, it is more accurate to envision a group of dipoles (two opposing charges separated by a small distance) swirling in a minor spiral. He and his team realized they could control these vortices with laser pulses containing a specific swirl.
The researchers adjusted the laser to emit circularly polarized light. Upon striking a strong-axis material (specifically a compound made of rubidium, iron, molybdenum, and oxygen), it induced rotation in the material’s atoms, altering the dipole’s direction of motion.
Team member Michael Forst from the Max Planck Institute for Structure and Mechanics of Matter remarked that while it has been established that light can effectively control materials—transforming conductors into insulators and vice versa—tailoring light’s properties for material control has presented a significant technical challenge.
“This serves as a strong proof of concept,” notes Theo Rasing at Radboud University in the Netherlands. He adds that this material adds to the growing array of options for constructing more efficient and stable memory devices, such as hard drives that store information in electromagnetic charge patterns.
However, the current experiments necessitate cooling the material to approximately -70°C.°C (-94°F). Additionally, because the team’s laser was relatively large, Forst indicates that more development is required before a practical device can realistically be constructed.
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Source: www.newscientist.com
