Cheaper and Strong Magnet That Could Rival Current Technology

The growing demand for high-performance magnets in modern technologies has raised concerns about cost and resource availability, particularly for widely used neodymium-based materials. As industries expand in automotive and electrical sectors, the need for alternatives that balance performance with sustainability has become increasingly urgent. Researchers are now turning attention toward materials that can maintain strong magnetic properties while relying on more abundant elements.

Professor Tetsuji Saito from Chiba Institute of Technology has explored this challenge by investigating samarium-iron-nitride magnets as a viable solution. His work, published in the peer-reviewed journal Inorganics, presents a detailed analysis of their production methods, structural characteristics, and magnetic performance. The study highlights how these materials could serve as a competitive alternative to conventional magnets while addressing supply concerns. As Professor Saito explains, “Thus, the development of samarium-based magnets, using the relatively abundant rare-earth element samarium, has become a focus of attention.”

The findings show that samarium-iron-nitride compounds can achieve strong magnetic behavior comparable to existing high-performance magnets. Two main structural forms were identified, each produced through different processes but both demonstrating high stability and efficiency. These materials exhibit strong resistance to demagnetization, high magnetization levels, and the ability to operate at elevated temperatures. In practical terms, this means they can perform reliably in demanding applications such as motors and electronic devices, offering performance close to current industry standards.

A key advancement lies in the production of samarium-iron-nitride powders, where nitrogen is introduced into samarium-iron structures to significantly enhance magnetic properties. The study reveals that this process dramatically increases coercivity, a critical factor for maintaining magnet strength. According to Professor Saito, “Both Th₂Zn₁₇-type and TbCu₇-type samarium-iron-nitride powders show excellent magnetic properties: high remanence magnetization, high intrinsic coercivity, and high Curie temperature.” These improvements are essential for ensuring long-term stability and efficiency in real-world applications.

Beyond powder production, the research also explores how these materials can be integrated into usable magnet forms. Bonded magnets, created by combining samarium-iron-nitride powders with resins or metals, are already being manufactured with promising results. These magnets can be shaped easily and produced at scale, making them suitable for commercial use. However, efforts to create fully dense sintered magnets—considered the gold standard for performance—are still ongoing due to challenges in maintaining structural stability during high-temperature processing.

The study concludes that while samarium-iron-nitride magnets are not yet a complete replacement for existing technologies, they represent a significant step forward in the search for cost-effective and sustainable magnetic materials. Their strong performance, combined with the relative abundance of samarium, positions them as a compelling candidate for future applications. Continued advancements in processing techniques and material stability are expected to further enhance their potential, paving the way for broader adoption in industries that rely heavily on high-performance magnets.

Journal Reference

Saito T. “Progress and Prospect of Sm-Fe-N Magnets.” Inorganics, 2025; 13: 322. DOI: https://doi.org/10.3390/inorganics13100322

About the Author

Prof. Tetsuji Saito graduated from Kyoto University, Department of Metal Processing, in 1984 and received his PhD in 1992, working on Neodymium-Iron-Boron (Nd-Fe-B) rare-earth permanent magnets. Since then, he has been studying rare-earth permanent magnets. Currently, he is a professor at Chiba Institute of Technology, where his research focuses on magnetic materials, including both soft and hard magnetic materials.