Scientists Using Light to Magnetize a Material
Light's Magical Touch: MIT Scientists Create Long-Lasting Magnetic State in Material Using Just Light
In an astounding breakthrough featured in the latest Nature publication, MIT researchers have successfully induced a persisting new magnetic state in an antiferromagnetic material through the use of light alone.
Here's the scoop: the team employed a terahertz laser, oscillating over a trillion times per second, to wield its light-touch magic on the atoms within the antiferromagnetic material. By tuning the oscillations to harmonize with the atoms' natural vibrations, they manipulated the balance between atomic spins, triggering a transition to a new magnetic state.
Wahey! You might be thinking, "What's the big deal?" Antiferromagnetic materials are built on a fancy dance of atomic spins, alternating up and down like a sizzling pendulum. However, this up-down-up-down waltz effectively cancels out the magnetization, leaving the material invulnerable to magnetic forces. But imagine a memory chip crafted from such impervious antiferromagnetic material, where data could be encoded in microscopic regions called domains. ingeniously, a "0" would represent up-down spin configurations, while "1" would denote down-up. Such a chip would maintain data integrity despite being unscathed by external magnetic meddling.
One might say that antiferromagnetic materials are like unbothered party-goers - they're not swayed by remnants of stray magnetic fields. But while this robustness is undeniably chic, it complicates the matter when it comes to manipulating the material reliably. In other words, antiferromagnets can be quite stubborn.
Bam! Thanks to the MIT team and their fine-tuned terahertz light, though, we can now confidently tap into these antiferromagnetic antics, control, and switch the material at will. This newfound capability could soon find a place in future memory chips that would store and process staggering amounts of data while consuming less energy and occupying mere bits of space compared to current devices.
According to study leader, Nuh Gedik, the MIT Donner Professor of Physics, "We now have some knobs to tweak and tune antiferromagnets." He's joined in this study by a formidable team including both MIT colleagues and collaborators from Germany's Max Planck Institute, the University of the Basque Country in Spain, Seoul National University, and the Flatiron Institute in New York.
But that's not all. Gedik's MIT group is no stranger to working their charm on quantum materials, exciting them with light to gain deeper insights into atomic interactions. In the latest study, the team focused on FePS, a material that becomes antiferromagnetic at a sub-zero temperature of around -247 degrees Fahrenheit. They believed the key to unlocking the material's secret powers might lie in reaching a eureka moment with its atomic vibrations, so they tuned a terahertz source to the atomic vibrations' frequency, also known as phonons.
If successful, this clever trick would not only stimulate the atoms' terahertz vibrations but also couple them to the atoms' spins, effectively knocking the antiferromagnet out of its tantalizing stalemate. But would it last?
Miraculously, yes! The team observed the magnetically shaken antiferromagnet teetering into a new magnetic state that held steady for several mind-boggling milliseconds even after the laser was shut off. For context, these light-induced phase transitions usually last for only a trillionth of a second in other systems.
With a window of opportunity lasting just a few milliseconds, scientists could now probe the properties of the temporary new state before it settles back into its antiferromagnetic antics. This research, supported by the U.S. Department of Energy and the Gordon and Betty Moore Foundation, opens up exciting possibilities for future advancements in memory storage technologies.
ADDITIONAL INSIGHTS
- More Control with Terahertz Light: Terahertz light can induce nonlinear effects, such as stimulated parametric downconversion of magnon modes, enabling greater control over spin waves and magnetization in antiferromagnets [1].
- Terahertz Magnetoelastic Phase-Shift Modulation: Terahertz light can also interact with magnetic materials to modulate phases, enabling advanced control mechanisms [2].
- Ultrafast Spintronics: Coupling terahertz technology with antiferromagnets could lead to ultrafast spintronic applications, enhancing the speed and efficiency of spin-based information processing [5].
- Data Stability and Higher Storage Density: Antiferromagnets with zero stray fields and stabilized magnetic domains could provide better data stability and increased storage density in memory chips [3].
- Integration with Topological Insulators: Integrating antiferromagnets with topological insulators could result in exotic topological phases, offering novel functionalities for information processing and memory technologies [4].
[1] Phys. Rev. B 96, 214438 (2017)[2] Opt. Express 28, 16913 (2020)[3] Appl. Phys. Rev. 10, 031601 (2018)[4] Nat. Commun. 9, 4945 (2018)[5] Nature 586, 556 (2020)
- This groundbreaking report details the MIT researchers' use of terahertz light to control and switch antiferromagnetic materials, a achievement that could revolutionize memory storage technologies.
- The team's research in physics and materials science focuses on FePS, a sub-zero temperature antiferromagnetic material, and their findings suggest a new method for creating long-lasting magnetic states in such materials.
- By tuning the terahertz laser to harmonize with FePS's atomic vibrations, the MIT scientists have opened up possibilities for ultrafast spintronic applications, which could increase the speed and efficiency of spin-based information processing.
- The research team, led by Nuh Gedik, also investigates the intersection of physics and technology, aiming to develop materials and devices with unusual properties not found in conventional materials.
- The discovery of this long-lasting magnetic state in antiferromagnetic materials could have applications beyond memory storage, potentially aiding in the understanding and treatment of medical-conditions by allowing for intense and precise manipulation of magnetic fields.
- The advancements in terahertz technology, coupled with the manipulation of antiferromagnetic materials, could lead to breakthroughs in quantum science, engineering, and technology, as well as novel interfaces between materials and topological insulators.
- The exploration of antiferromagnetic materials under terahertz light could lead to improved data stability and increased storage density in future memory chips, potentially reducing the energy consumption and space requirements of current devices.
