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Scientists Race to Engineer a New Magnet for Electronics

2010-04-12 09:26:37

Jeremy Hsu

TechNewsDaily Contributor

LiveScience.com Jeremy Hsu

technewsdaily Contributor

livescience.com Sat Apr 10, 1:55 pm ET

A magnet at the heart of high-tech products such as cell phones and hybrid cars

relies upon an increasingly scarce supply of the rare earth element known as

neodymium. Now one of the original inventors of that magnet hopes to create a

new generation of magnetic materials that can ease or break free of that

dependence.

The neodymium-iron-boron magnet represents the most powerful commercial magnet

available today, and has a starring role in many technologies crucial to the

U.S. economy and defense. But the U.S. overwhelmingly relies upon China for its

supply of neodymium and other rare earth minerals, and China has warned that

its own domestic demand may soon force it to cut off that supply.

That means the U.S. may face a shortage of neodymium and other rare earths,

unless it spends the time and money to begin mining its own fairly untapped

reserves. The possibility of a shortage has also led to renewed research aimed

at developing magnets less dependent upon neodymium.

"It's been 27 or 28 years since the discovery of neodymium-iron-boron

(Nd-Fe-B), and we have not yet found a better magnet," said George

Hadjipanayis, a physicist at the University of Delaware and co-inventor of the

Nd-Fe-B magnet.

Hadjipanayis leads a collaborative research effort with $4.6 million in funding

from ARPA-E, the U.S. Department of Energy's agency that backs high-risk but

potentially high-payoff projects.

Nd-Fe-B magnets have worked well for everything from computer hard drives to

wind turbines and Toyota's Prius because of their exceptional magnetic strength

- the energy product of such magnets can reach 50 million or even 60 million

megagauss-oersteds (MGOe). By comparison, the energy product of the more common

ferrite magnets is just 4 million to 5 million MGOe.

"The higher the strength of the magnet, the smaller the amount of magnet you

need for a particular application," Hadjipanayis told TechNewsDaily. He added

that Nd-Fe-B magnets play a crucial part in building ever-smaller electronic

devices. (Read "The Common Elements of Innovation.")

Three routes to a better magnet

Hadjipanayis and his fellow researchers plan to pursue three different routes

to possibly achieving a next-gen magnet breakthrough.

First, the U.S. Department of Energy's Ames Laboratory in Iowa plans to

investigate new materials based on combinations of rare earths, transition

metal elements and some elements that have not been studied before in magnets.

Many such elements require special working lab conditions under high pressures

or temperatures, and create additional challenges because they have high

reactivity or toxicity.

Second, an approach headed by the University of Nebraska will try to develop a

rare earth-free magnet. This has proven a challenge because existing magnets

without rare earths have much lower magnetic strength, but there are some

theoretical ideas about changing the crystal symmetry of iron-cobalt alloys by

using some non-magnetic elements as substitutes.

Third, Hadjipanayis and the University of Delaware will try to create a new

magnetic material that combines the best properties of Nd-Fe-B and iron. The

material would ideally end up with high magnetization, and also strongly resist

demagnetization.

Simulations have predicted that a next-gen magnet built this way could have a

magnetic strength of more than 100 million MGOe, and might also slash neodymium

use in magnets by 30 or 40 percent.

Feeling the pressure

All efforts to create such magnetic material have faltered over the past few

decades, but Hadjipanayis sees hope in a new bottom-up approach that mixes

nanoparticles of Nd-Fe-B at the incredibly tiny scale of just billionths of a

meter, or far smaller than the width of a human hair.

Other research participants include Northeastern University, Virginia

Commonwealth University and the Electron Energy Corporation - one of the last

U.S. companies making rare-earth magnets.

The group has put together an ambitious timeline that involves two years for

experimenting with materials, before hopefully putting together a new magnet

prototype in the third year.

"It's a fast-moving program, so I already started feeling the pressure,"

Hadjipanayis said. "Hopefully we'll have a breakthrough that leads to some

permanent magnets."