Scientists around the globe are delving into the mysteries of terahertz waves, aiming to close the “terahertz gap.” This gap refers to the frequency range of terahertz waves, which lie between microwaves and infrared light, and remains largely unexplored. Only recently have technological advancements allowed researchers to generate these waves. A major breakthrough has been made at Tohoku University, shedding light on these elusive waves and advancing our understanding.
Researchers from the Advanced Institute for Materials Research (WPI-AIMR) and the Graduate School of Engineering have identified a groundbreaking magnetic material that produces terahertz waves with an intensity about four times greater than that of typical magnetic materials.
Terahertz waves have unique properties that make them incredibly useful across various industries, including imaging, medical diagnostics, security screening, and biotechnology. Assistant Professor Ruma Mandal (WPI-AIMR) explains, “Terahertz waves have low photon energies and don’t emit ionizing radiation like X-rays. This means they could be safer for medical imaging and microscopy, causing less damage to tissues or samples.”
Driven by these potential applications, the Tohoku University team set out to develop an efficient, compact, durable, and affordable terahertz wave emitter. They turned to Weyl magnets, a type of topological material known for their significant anomalous Hall effect, which makes them ideal for generating terahertz waves. In their study, they created and tested single-crystal thin-film samples of a Weyl magnet made from a cobalt-manganese-gallium Heusler alloy.
Their findings revealed that the unique topological electronic structure of Weyl magnets enhances the photo-induced terahertz waves. This advancement enriches our understanding of the interplay between light and spin in these materials.
Professor Shigemi Mizukami adds, “Although the terahertz wave intensity is still lower than that of spin-excitation terahertz emitters developed so far, our simpler structure does not require costly heavy metals like platinum.”
Mandal and the team successfully demonstrated that this magnetic material can generate terahertz waves, paving the way for its use in spintronic devices and other critical applications. This discovery in a rapidly evolving field could shape the future of next-generation technologies.
This research was published in NPG Asia Materials on June 7, 2024.
Looking Ahead
Terahertz technology promises to transform various sectors. In medical diagnostics, terahertz waves can produce high-resolution images of tissues without the risks associated with X-rays. For security, they offer a non-invasive method for inspecting packages and luggage, capable of detecting hidden weapons or contraband. In biotechnology, terahertz waves enable the analysis of molecular compositions, providing deeper insights into biological processes.
Efficient terahertz wave generators could also revolutionize wireless communications, potentially offering faster data transfer rates than current microwave technology. This could lead to breakthroughs in high-speed internet and next-generation communication networks.
In summary, the discovery of this new magnetic material at Tohoku University marks a significant leap in terahertz research, with far-reaching implications for science and industry.
Publication Details:
Title: Topologically-Influenced Terahertz Emission in Co2MnGa with Large Anomalous Hall Effect
Authors: Ruma Mandal, Ren Momma, Kazuaki Ishibashi, Satoshi Iihama, Kazuya Suzuki, and Shigemi Mizukami
Journal: NPG Asia Materials
DOI: https://doi.org/10.1038/s41427-024-00545-9
Subtly charming pop culture geek. Amateur analyst. Freelance tv buff. Coffee lover