The news from Beijing last October sent a jolt of alarm through wide swaths of American industry.
For the second time in less than a year, China had restricted its export of metals called rare earths, a class of 17 strategic minerals for which it controls most of the world’s supply. Because they can be used to make super-strong magnets, rare earths play an essential role in a wide array of gadgetry, from earbuds to weapons systems to electric cars.
But as the Trump administration raced to secure alternative sources of the critical minerals, Dartmouth engineering professor Ian Baker already had been working for years on a different approach that might make the United States less vulnerable: inventing new magnets that don’t contain any rare earths.
In his Thayer School lab, Baker designs and creates new magnets from more readily available materials, such as manganese and aluminum. His magnets aren’t as strong as those made with rare earths, but they’re especially good at resisting demagnetization, making them a potential fit for certain applications such as elevators.
“There has been a realization for 15 years or more that this is a problem,” Baker says, “but it’s becoming more urgent.”
Despite the name, the metals at the center of this geopolitical showdown are not especially rare, says the Oxford-trained Baker, who joined the Dartmouth faculty in 1982. Rare earths are far more abundant in the earth’s crust than platinum, gold, or silver.
The problem is that rare-earth deposits are intermingled with a host of other minerals, and the separation process is both costly and environmentally toxic.
China built its dominance in the field because of its willingness to bear those costs, says economist Heidi Crebo-Rediker ’90, who follows the issue closely. Although the United States has recently started to ramp up its rare-earth mining and processing capacity, that strategy alone won’t allow the country to catch up, she says. China got a head start decades ago.
“It’s hard to out-mine, out-fund, and outprocess China,” says Crebo-Rediker, a senior fellow at the Council on Foreign Relations.
A better solution, according to a recent report she coauthored for the nonprofit think tank, is to leapfrog China through innovation.
That includes developing substitute materials such as the ones Baker works on, Crebo-Rediker says. It also includes recovering rare earths from mining waste and discarded electronics. Yet the United States currently ships much of the latter to the very country it needs to catch up with: China.
“We need to change our entire mentality toward waste and think of it as America’s next mine,” says Crebo-Rediker, who majored in government and Russian-area studies at Dartmouth before earning a master’s at the London School of Economics.
To end its reliance on China for rare earths, she says, the United States needs a comprehensive strategy to identify the best emerging technologies and support them with a mix of public and private financing. Cooperation with allies also will be key.
At Dartmouth, Baker often starts with theoretical calculations to predict which combinations of materials will yield the best magnets. The idea of using manganese and aluminum, for example, was conceived by others, but postdoctoral fellows at the College calculated they could make the magnets more durable by incorporating a hint of titanium.
To put such theories to the test, Baker and his collaborators make small samples of magnets with a variety of techniques, including a sophisticated type of 3-D printing done at the University of California. Manganese-aluminum-titanium magnets were made at Dartmouth with a device called an arc melter, in which a tungsten-tipped rod heats the metals together inside a sealed chamber.
It turned out that adding titanium to the mix made these magnets more resistant to demagnetization, Baker says, but only to a point. Using more than a trace of titanium has the opposite effect.
“There’s actually a sweet spot in there,” he says. “We’re not quite sure why.”
To understand why rare earths are so valuable, recall that magnetism and electricity are closely related. A rotating magnet can be used to generate electricity (think wind turbines), while electricity can be used to rotate a magnet (the principle behind many electric motors).
Because the manganese-aluminum-titanium magnets aren’t as strong as those made from rare earths, they must be larger to pack the same punch, Baker says. That means they aren’t practical for applications where space is at a premium, such as in electric cars, though they’d be a good fit for motors in elevators or moving walkways.
For most uses, the manganese-aluminum magnets would need to be stronger. Another approach Baker plans to test is beefing them up with small amounts of a stronger magnetic material made from iron and cobalt. Years of research lie ahead before these alternative magnets could be ready for widespread application.
Yet Crebo-Rediker says time is at a premium, given China’s recent practice of abruptly imposing new controls on its exports. In October, for example, Beijing announced that importers of Chinese rare-earth magnets would have to detail how the materials would be used—a measure critics likened to formalized industrial espionage.
Although the Chinese government later backed off on some of its demands, the Trump administration redoubled efforts to secure other sources of the metals. That included proposing a multibillion-dollar plan to stockpile rare earths and other critical minerals at sites throughout the United States as well as meeting with allies to establish alternate supply chains—moves generally well received by manufacturers. President Trump also cited rare-earth deposits in Greenland when he blustered about taking control of that island, though experts say mining those deposits would be impractical.
Could scientists such as Baker innovate a way out of this logjam? Crebo-Rediker says we have no choice but to let them try.
“The year 2025 was a very big wakeup call for the United States and the global industrial world,” she says. “I would love to see someone from Dartmouth crack this problem.”
Tom Avril was a longtime science writer at The Philadelphia Inquirer and is now writing a novel.
