FOR much of the last century, the straightforward solution to making a car perform better has been to install a bigger engine. In the hybrids and electric cars of coming years, however, the answer might be installing motors with more powerful magnets.

Until the 1980s, the most powerful magnets available were those made from an alloy containing samarium and cobalt. But mining and processing those metals presented challenges: samarium, one of 17 so-called rare earth elements, was costly to refine, and most cobalt came from mines in unstable regions of Africa.

In 1982, when researchers at General Motors developed a magnet based on neodymium, it seemed that an ideal alternative had arrived. While neodymium is also one of the rare earth metals — a misleading name, as they are actually fairly common, just widely dispersed — it is more abundant than samarium, and at the time it was cheaper. When combined with iron and boron, both readily available elements, it produced mighty magnets.

In the electric drive motor of a hybrid car, for instance, just a kilogram, or 2.2 pounds, of neodymium-based magnets can deliver 80 horsepower, enough to move a 3,000-pound vehicle like the Toyota Prius. Neodymium is an ideal magnet material because it helps to retain a magnetic charge during all driving conditions, and when dysprosium is added to the alloy, performance at high temperatures is preserved.