Neodymium

Neodymium was isolated in 1885 by Carl Auer von Welsbach at the same time as praseodymium, when he separated the supposed element didymium into two. He named it neodymium, from the Greek neos didymos, new twin. Neodymium is a soft, silvery rare-earth metal, most important today for the neodymium-iron-boron magnets, the strongest permanent magnets known, which drive everything from headphones to wind turbines and electric motors.

Beyond its magnets, neodymium tints glass and ceramics a delicate violet and forms the doped crystals and glasses of powerful solid-state lasers used in industry, medicine and research. The powerful neodymium-iron-boron magnet itself was invented independently in 1984 by General Motors researcher John Croat in the United States and by Masato Sagawa at Sumitomo Special Metals in Japan, a near-simultaneous dual discovery that led to years of patent litigation between the two companies before cross-licensing agreements let both continue producing what remains, four decades on, the strongest type of permanent magnet commercially available. These magnets, though barely a few decades old, are now judged essential enough to modern manufacturing that several governments classify neodymium among their most strategically critical minerals.

Neodymium shares its origin story with praseodymium: both emerged when Auer von Welsbach broke apart didymium, the twin, revealing that Mosander's single element had all along been a pair. Neodymium, the new twin, took the larger share and the more surprising properties, its salts a delicate pink or lilac and its magnetic behaviour extraordinary. The element has no mythological or alchemical past, being a late product of rare-earth chemistry, but it has acquired an outsized modern significance, since the powerful magnets it forms are indispensable to the compact motors and generators of contemporary technology. Its name, the new twin, keeps alive the memory of the illusory single element from which it and praseodymium were finally distinguished.

Large neodymium-glass laser arrays, most famously the 192 beams of the National Ignition Facility in California, are also central to modern fusion energy research, where banks of neodymium-doped glass amplifiers briefly concentrate more power than the entire United States grid to compress a tiny fuel pellet in the hope of igniting self-sustaining fusion. The same doped glass, at far lower power, is the workhorse material behind many industrial cutting and engraving lasers in everyday manufacturing use.