Terahertz waves are attracting increasing attention from researchers worldwide as they seek to unravel the mysteries of the "terahertz gap." Positioned between microwaves and infrared light, terahertz waves remain a relatively unexplored frontier, with much still unknown about their properties. The technology to generate these waves has only recently been developed, but advancements are accelerating. One such breakthrough comes from researchers at Tohoku University, who have made significant progress in understanding these waves and closing the knowledge gap.

Figure 1. The Proposed Method. (Credit: Shigemi Mizukami)

Researchers from the Advanced Institute for Materials Research (WPI-AIMR) and the Graduate School of Engineering at Tohoku University have discovered a novel magnetic material capable of generating terahertz waves at an intensity approximately four times greater than typical magnetic materials. This discovery could pave the way for a range of industrial applications, from imaging and medical diagnostics to security and biotechnology. Figure 1 shows (a) Weyl magnet: schematic diagram of a crystal of cobalt-manganese-gallium Heusler alloy (Co2MnGa). (b) Light-induced terahertz waves [2].

Assistant Professor Ruma Mandal from WPI-AIMR highlights the potential of this technology, stating, "Terahertz waves have low photon energies and unlike X-rays, they don't emit ionizing radiation. So, if they are used for patient imaging or microscopes, they may be less damaging to tissues or samples."

With this in mind, the team sought to develop an efficient, compact, durable, and cost-effective terahertz wave emitter. Weyl magnets, a class of topological materials, are known to produce a significant anomalous Hall effect, making them ideal for generating terahertz waves. For this study, the researchers prepared and studied single-crystal thin-film samples of a Weyl magnet made from a cobalt-manganese-gallium Heusler alloy under various conditions.

The results showed that the giant anomalous Hall effect, which is tied to the topological electronic structure of Weyl magnets, amplified the generation of photo-induced terahertz waves. This discovery not only enhances our understanding of the interaction between light and spin in Weyl magnets, but it also offers a glimpse into the future of terahertz wave applications [1].

While the intensity of the generated terahertz waves is still lower compared to spin-excitation terahertz emitters developed so far, Professor Shigemi Mizukami points out, "The structure is simpler and expensive heavy metals such as platinum are no longer required."

Mandal and their colleagues have successfully demonstrated the capability of this magnetic material to generate terahertz waves, which holds promise for spintronic devices and other cutting-edge applications. This breakthrough is a significant step forward in a rapidly emerging field that could shape the next generation of technologies.

This research was published in NPG Asia Materials on June 7, 2024.

Source: Tohoku University

References:

1. https://phys.org/news/2024-06-generation-intense-terahertz-magnetic-material.html
2. https://www.eurekalert.org/news-releases/1048830

Cite this article:

Hana M (2024), New Magnetic Material Could Revolutionize Terahertz Wave Technology for Future Applications, AnaTechmaz, pp. 76