Northeastern University

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

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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.



2 Comments

  1. This should attract attention to Northeastern research.

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