The world’s strongest magnets in a billionth of the time

There’s a great story in the News@Northeastern today about Laura Lewis’ ARPA-​​E grant — a $3.5million award from the Depart­ment of Energy, which Lewis’ team will use to iden­tify new, super-​​strong mag­netic mate­rials. As Matt Col­lette explains in the article, China has a hold on the rare earth industry, cur­rently the main ele­ment used to make super-​​strong mag­nets. Last year China slowed rare-​​earth metal pro­duc­tion to raise prices, and since super-​​magnets are essen­tial to pretty much all of the tech­nolo­gies we can’t seem to live without any­more (cell phones, com­puters, etc.), we clearly need some other means of pro­ducing them. So that’s exactly Lewis’ plans to do with the new grant.

But I have some other ques­tions: What the heck is a rare earth metal anyway (I’m hoping my inor­ganic chem­istry pro­fessor isn’t reading this) and why does Lewis think she can make some­thing better?

When you look at the peri­odic table, which is nicely arranged based on ele­mental prop­er­ties, the rare earths fall (mostly) in that second to last row — the lan­thanides. They are ele­ments with hard-​​to-​​pronounce names like neodymium and yttrium and they’re actu­ally rather plen­tiful in the earth’s crust. The “rare” in the name comes from the fact that they’re hard to isolate.

Rare earth mag­nets are alloys of these metals. A magnet made of neodymium, iron and boron is ridicu­lously strong (“the strongest magnet on earth,” in fact, according to Lewis). She had one about the size of a quarter stuck to a steel block on her desk. It was not pos­sible to lift the dinky little magnet off the block — I tried. If you absolutely needed to sep­a­rate them, you’d have to slide the magnet off the edge block, but short steel walls pre­vent that. Lewis told me not to push the magnet into one of the cor­ners because it was very hard to get it out (it hap­pened to her once).

Rare earth mag­nets aren’t nat­u­rally occur­ring — they were first syn­the­sized in the early six­ties. Reg­ular mag­nets from things like iron and nickel aren’t nearly as strong…normally.

In mete­orites, which take bil­lions of years to cool off, iron-​​nickel alloy have been found with supremely orga­nized struc­tures, giving them super-​​strong mag­netic qual­i­ties. Unfor­tu­nately, we don’t have bil­lions of years. Lewis’ team will use other ele­ments to help urge it into the super strong mag­netic configuration.

Another approach, which doesn’t mimic the mete­orite method, will build mag­nets from the ground up using nano-​​particles pre­cisely arranged to yield stronger mag­netic qualities.

ARPA-​​E awards tend to fall into the “high-​​risk/​high-​​reward” cat­e­gory, and this is no excep­tion. If Lewis’ team is suc­cessful, it would make a whole industry of elec­tric vehi­cles and renew­able power gen­er­a­tors eco­nom­i­cally viable. If they aren’t successful…well, we’ll cross that bridge if we get there.