Dysprosium and terbium are added to neodymium magnets for one reason: to raise their resistance to demagnetization so they keep working when hot or when a strong opposing field is present. They are what lets a neodymium magnet run at temperatures well above the roughly 80°C limit of a standard grade [1]. They are also among the elements whose export China licenses, and almost all of the world's heavy rare earth processing happens there [3].
Where they matter
Traction and servo motors, generators, and any assembly where the magnet sits next to a hot winding or in a strong reverse field. The letters after the grade number (H, SH, UH, EH) indicate higher coercivity and operating temperature [1]. Reaching them generally takes more dysprosium or terbium, which adds cost [1].
Where they don't
Holding magnets, sensors at room temperature, sound devices, small motors that do not run hot, and everyday uses such as the magnets in appliances [2]. Standard N-series grades are enough there, and over-specifying a high-temperature grade only adds cost and supply risk.
Ways to reduce exposure
First, work out the real maximum temperature and opposing field at the magnet's position, then choose the lowest grade with a safety margin. Second, ask suppliers about low-heavy-rare-earth or heavy-rare-earth-free grades. Third, note that samarium cobalt is not an escape route, because samarium is also under licence [3]. Ferrite is the only common option with no rare earths at all.
Our product table shows the grade range and the heavy-rare-earth-free option for each size. Send us your working temperature and we will suggest the lowest-risk grade.
References
[1] Wikipedia contributors. Neodymium magnet. Wikipedia, The Free Encyclopedia. https://en.wikipedia.org/wiki/Neodymium_magnet
[2] S&P Global. (2026, January 27). Rare earth supply bottlenecks set to persist in 2026. https://www.spglobal.com/energy/en/news-research/latest-news/metals/012726-rare-earth-supply-bottlenecks-set-to-persist-in-2026
[3] Tech Times. (2026, October 2). Rare earth magnets: China's November 10 deadline and the US gap money can't close. https://www.techtimes.com/articles/328392/20261002/rare-earth-magnets-chinas-november-10-deadline-us-gap-money-cant-close.htm