https://news.mit.edu/2024/physicists-magnetize-material-using-light-1218 Skip to content | Massachusetts Institute of Technology MIT Top Menu| * Education * Research * Innovation * Admissions + Aid * Campus Life * News * Alumni * About MIT * More | Search MIT Search websites, locations, and people [ ] See More Results Suggestions or feedback? MIT News | Massachusetts Institute of Technology Subscribe to MIT News newsletter Browse Enter keywords to search for news articles: [ ] Submit Browse By Topics View All - Explore: * Machine learning * Sustainability * Startups * Black holes * Classes and programs Departments View All - Explore: * Aeronautics and Astronautics * Brain and Cognitive Sciences * Architecture * Political Science * Mechanical Engineering Centers, Labs, & Programs View All - Explore: * Abdul Latif Jameel Poverty Action Lab (J-PAL) * Picower Institute for Learning and Memory * Media Lab * Lincoln Laboratory Schools * School of Architecture + Planning * School of Engineering * School of Humanities, Arts, and Social Sciences * Sloan School of Management * School of Science * MIT Schwarzman College of Computing View all news coverage of MIT in the media - Listen to audio content from MIT News - Subscribe to MIT newsletter - Close Breadcrumb 1. MIT News 2. Physicists magnetize a material with light Physicists magnetize a material with light The technique provides researchers with a powerful tool for controlling magnetism, and could help in designing faster, smaller, more energy-efficient memory chips. Jennifer Chu | MIT News Publication Date: December 18, 2024 Press Inquiries Press Contact: Abby Abazorius Email: abbya@mit.edu Phone: 617-253-2709 MIT News Office Media Download Three people observe a table of equipment, with pink and blue lighting. | Download Image Caption: "Generally, such antiferromagnetic materials are not easy to control," Nuh Gedik says, pictured in between Tianchuang Luo, left, and Alexander von Hoegen. Additional MIT co-authors include Batyr Ilyas, Zhuquan Zhang, and Keith Nelson. Credits: Photo: Adam Glanzman Lens and equipment on the table | Download Image Caption: Using carefully tuned terahertz light, the MIT team was able to controllably switch an antiferromagnet to a new magnetic state. The transition persisted for a surprisingly long time, over several milliseconds, even after the laser was turned off. Credits: Photo: Adam Glanzman Nuh Gedik portrait with blue lighting. | Download Image Caption: "People have seen these light-induced phase transitions before in other systems, but typically they live for very short times on the order of a picosecond, which is a trillionth of a second," Gedik says. Credits: Photo: Adam Glanzman *Terms of Use: Images for download on the MIT News office website are made available to non-commercial entities, press and the general public under a Creative Commons Attribution Non-Commercial No Derivatives license. You may not alter the images provided, other than to crop them to size. A credit line must be used when reproducing images; if one is not provided below, credit the images to "MIT." Close Three people observe a table of equipment, with pink and blue lighting. Caption: "Generally, such antiferromagnetic materials are not easy to control," Nuh Gedik says, pictured in between Tianchuang Luo, left, and Alexander von Hoegen. Additional MIT co-authors include Batyr Ilyas, Zhuquan Zhang, and Keith Nelson. Credits: Photo: Adam Glanzman Lens and equipment on the table Caption: Using carefully tuned terahertz light, the MIT team was able to controllably switch an antiferromagnet to a new magnetic state. The transition persisted for a surprisingly long time, over several milliseconds, even after the laser was turned off. Credits: Photo: Adam Glanzman Nuh Gedik portrait with blue lighting Caption: "People have seen these light-induced phase transitions before in other systems, but typically they live for very short times on the order of a picosecond, which is a trillionth of a second," Gedik says. Credits: Photo: Adam Glanzman Previous image Next image MIT physicists have created a new and long-lasting magnetic state in a material, using only light. In a study appearing today in Nature, the researchers report using a terahertz laser -- a light source that oscillates more than a trillion times per second -- to directly stimulate atoms in an antiferromagnetic material. The laser's oscillations are tuned to the natural vibrations among the material's atoms, in a way that shifts the balance of atomic spins toward a new magnetic state. The results provide a new way to control and switch antiferromagnetic materials, which are of interest for their potential to advance information processing and memory chip technology. In common magnets, known as ferromagnets, the spins of atoms point in the same direction, in a way that the whole can be easily influenced and pulled in the direction of any external magnetic field. In contrast, antiferromagnets are composed of atoms with alternating spins, each pointing in the opposite direction from its neighbor. This up, down, up, down order essentially cancels the spins out, giving antiferromagnets a net zero magnetization that is impervious to any magnetic pull. If a memory chip could be made from antiferromagnetic material, data could be "written" into microscopic regions of the material, called domains. A certain configuration of spin orientations (for example, up-down) in a given domain would represent the classical bit "0," and a different configuration (down-up) would mean "1." Data written on such a chip would be robust against outside magnetic influence. For this and other reasons, scientists believe antiferromagnetic materials could be a more robust alternative to existing magnetic-based storage technologies. A major hurdle, however, has been in how to control antiferromagnets in a way that reliably switches the material from one magnetic state to another. "Antiferromagnetic materials are robust and not influenced by unwanted stray magnetic fields," says Nuh Gedik, the Donner Professor of Physics at MIT. "However, this robustness is a double-edged sword; their insensitivity to weak magnetic fields makes these materials difficult to control." Using carefully tuned terahertz light, the MIT team was able to controllably switch an antiferromagnet to a new magnetic state. Antiferromagnets could be incorporated into future memory chips that store and process more data while using less energy and taking up a fraction of the space of existing devices, owing to the stability of magnetic domains. "Generally, such antiferromagnetic materials are not easy to control," Gedik says. "Now we have some knobs to be able to tune and tweak them." Gedik is the senior author of the new study, which also includes MIT co-authors Batyr Ilyas, Tianchuang Luo, Alexander von Hoegen, Zhuquan Zhang, and Keith Nelson, along with collaborators at the Max Planck Institute for the Structure and Dynamics of Matter in Germany, University of the Basque Country in Spain, Seoul National University, and the Flatiron Institute in New York. Off balance Gedik's group at MIT develops techniques to manipulate quantum materials in which interactions among atoms can give rise to exotic phenomena. "In general, we excite materials with light to learn more about what holds them together fundamentally," Gedik says. "For instance, why is this material an antiferromagnet, and is there a way to perturb microscopic interactions such that it turns into a ferromagnet?" In their new study, the team worked with FePS[3] -- a material that transitions to an antiferromagnetic phase at a critical temperature of around 118 kelvins (-247 degrees Fahrenheit). The team suspected they might control the material's transition by tuning into its atomic vibrations. "In any solid, you can picture it as different atoms that are periodically arranged, and between atoms are tiny springs," von Hoegen explains. "If you were to pull one atom, it would vibrate at a characteristic frequency which typically occurs in the terahertz range." The way in which atoms vibrate also relates to how their spins interact with each other. The team reasoned that if they could stimulate the atoms with a terahertz source that oscillates at the same frequency as the atoms' collective vibrations, called phonons, the effect could also nudge the atoms' spins out of their perfectly balanced, magnetically alternating alignment. Once knocked out of balance, atoms should have larger spins in one direction than the other, creating a preferred orientation that would shift the inherently nonmagnetized material into a new magnetic state with finite magnetization. "The idea is that you can kill two birds with one stone: You excite the atoms' terahertz vibrations, which also couples to the spins," Gedik says. Shake and write To test this idea, the team worked with a sample of FePS[3] that was synthesized by colleages at Seoul National University. They placed the sample in a vacuum chamber and cooled it down to temperatures at and below 118 K. They then generated a terahertz pulse by aiming a beam of near-infrared light through an organic crystal, which transformed the light into the terahertz frequencies. They then directed this terahertz light toward the sample. "This terahertz pulse is what we use to create a change in the sample," Luo says. "It's like 'writing' a new state into the sample." To confirm that the pulse triggered a change in the material's magnetism, the team also aimed two near-infrared lasers at the sample, each with an opposite circular polarization. If the terahertz pulse had no effect, the researchers should see no difference in the intensity of the transmitted infrared lasers. "Just seeing a difference tells us the material is no longer the original antiferromagnet, and that we are inducing a new magnetic state, by essentially using terahertz light to shake the atoms," Ilyas says. Over repeated experiments, the team observed that a terahertz pulse successfully switched the previously antiferromagnetic material to a new magnetic state -- a transition that persisted for a surprisingly long time, over several milliseconds, even after the laser was turned off. "People have seen these light-induced phase transitions before in other systems, but typically they live for very short times on the order of a picosecond, which is a trillionth of a second," Gedik says. In just a few milliseconds, scientists now might have a decent window of time during which they could probe the properties of the temporary new state before it settles back into its inherent antiferromagnetism. Then, they might be able to identify new knobs to tweak antiferromagnets and optimize their use in next-generation memory storage technologies. This research was supported, in part, by the U.S. Department of Energy, Materials Science and Engineering Division, Office of Basic Energy Sciences, and the Gordon and Betty Moore Foundation. Share this news article on: * X * Facebook * LinkedIn * Reddit * Print Paper Paper: "Terahertz field-induced metastable magnetization near criticality in FePS3" Check for open access version(s) of the research mentioned in this article. Related Links * Nuh Gedik * Department of Physics * School of Science Related Topics * Electronics * Light * Magnets * Photonics * Physics * Research * School of Science Related Articles multiferroic state in 2D material Physicists observe an exotic "multiferroic" state in an atomically thin material A painted cartoon of a mountain with paths leading up and down and stick figures on the paths Scientists discover a mysterious transition in an electronic crystal Illustration showing two fuzzy spheres joined together, side by side Physicists detect a hybrid particle held together by uniquely intense "glue" Researchers confirmed the existence of electronic waves that are frozen at a transition temperature of 125 kelvins and start "dancing together" in a collective oscillating motion as the temperature is lowered. In this illustration, a red laser beam triggers the dance of the newly discovered electronic waves in magnetite. Dancing electrons solve a longstanding puzzle in the oldest magnetic material Previous item Next item More MIT News A student holds an espresso cup at a lab table while talking to her two classmates. Coffee fix: MIT students decode the science behind the perfect cup Undergraduate class blends science, hands-on experimentation, and a love for coffee to fuel curiosity. Read full story - Halie Olson, Kristina Johnson, and Anila D'Mello pose for photo with projected images of MRI brain scans in background Personal interests can influence how children's brains respond to language McGovern Institute neuroscientists use children's interests to probe language in the brain. Read full story - Joseph DeCarolis gestures with both hands while speaking at a lectern The role of modeling in the energy transition At the MITEI Fall Colloquium, the administrator of the US Energy Information Administration explained why long-term energy models are not forecasting tools -- and why they're still vitally important. Read full story - Down power lines at the center of a dirt road with partial view of a house in the upper left corner. How hard is it to prevent recurring blackouts in Puerto Rico? Using the island as a model, researchers demonstrate the "DyMonDS" framework can improve resiliency to extreme weather and ease the integration of new resources. Read full story - Two photos show the lab equipment and a white paper that looks clean. New filter captures and recycles aluminum from manufacturing waste MIT engineers designed a nanofiltration process that could make aluminum production more efficient while reducing hazardous waste. Read full story - Sepia-tone headshot of Loren Graham Loren Graham, professor emeritus of the history of science, dies at 91 Longtime MIT faculty member, award-winning author, and HASTS program co-founder was an expert in the influence of social context on science, and the organization of science in Russia and the Soviet Union. Read full story - * More news on MIT News homepage - More about MIT News at Massachusetts Institute of Technology This website is managed by the MIT News Office, part of the Institute Office of Communications. News by Schools/College: * School of Architecture and Planning * School of Engineering * School of Humanities, Arts, and Social Sciences * MIT Sloan School of Management * School of Science * MIT Schwarzman College of Computing Resources: * About the MIT News Office * MIT News Press Center * Terms of Use * Press Inquiries * Filming Guidelines * RSS Feeds Tools: * Subscribe to MIT Daily/Weekly * Subscribe to press releases * Submit campus news * Guidelines for campus news contributors * Guidelines on generative AI Massachusetts Institute of Technology MIT Top Level Links: * Education * Research * Innovation * Admissions + Aid * Campus Life * News * Alumni * About MIT * Join us in building a better world. Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA, USA Recommended Links: * Visit * Map (opens in new window) * Events (opens in new window) * People (opens in new window) * Careers (opens in new window) * Contact * Privacy * Accessibility * + Social Media Hub + MIT on X + MIT on Facebook + MIT on YouTube + MIT on Instagram