Dysprosium

About Dysprosium

Dysprosium has the highest magnetic moment per atom of any element in its ground state — about 10.6 Bohr magnetons from the unpaired f-electrons in [Xe] 4f¹⁰ — and the highest neutron absorption cross-section of any stable lanthanide outside of gadolinium. Both of those numbers explain why it's now on every Critical Materials list a government publishes. In sintered Nd₂Fe₁₄B magnets the coercivity collapses around 80 °C; doping with a few atomic percent of Dy at the grain boundaries pushes the operating ceiling well past 180 °C, which is the difference between a traction motor that survives a Phoenix highway and one that demagnetizes. That's why an EV traction motor uses roughly 100 g of dysprosium and a direct-drive offshore wind turbine uses tens of kilograms. Separating Dy from the other heavy lanthanides is genuinely hard — the ionic radii differ by picometers across the 4f series, so production runs through dozens of solvent-extraction stages with phosphonate extractants. About 90% of the supply still comes from a handful of clay deposits in southern China.