Reducing the World's Reliance on Rare Earth Magnets

Interview conducted by Stuart MilneJun 10 2015

AZoNano recently published a story from Virginia Commonwealth University about novel magnetic nanoparticles which could reduce the world's reliance on rare earth magnets. When collected in powders this new nanomaterial has magnetic properties that rival current rare earth magnets. The new material shows huge potential for clean energy applications. Dr. Shiv Khanna and Dr. Everett Carpenter, spoke to AZoNano about why these new nanoparticles are important and the benefits they offer.

Could you please give our readers a brief introduction to the new magnetic nanoparticles you have developed?

Small nanoparticles of magnetic materials undergo a reduction in magnetic anisotropy that allows the magnetic direction to fluctuate with time under ordinary conditions. This limits the size that can be used for memory storage.

What we have synthesized are new CoFe₂C nanoparticles that are highly magnetized, exhibit stable magnetic efficiency with time, and can retain magnetic information up to 517°C (790 K). Apart from storing data, assemblies of these particles have energy products that can rival the currently used permanent magnets.

Image Credits: Peter Sobolev /shutterstock.com

Why is it so important to create a magnetic material that reduces the reliance on rare earth elements?

The extraction of rare earth elements generates radioactive waste.

This is the reason that 70-80% of the current rare earths are produced in China. Unless technology is developed to deal with all the waste, developing alternate technologies is a useful direction.

Will the magnets developed using these material have comparable remenance and coercivity to the strongest permanent magnets currently available (namely NdFeB)?

No, the current material does not have coercivity of current rare earths. We have just formed the first product and its in the very early stages of development.

We have a pathway towards developing the product. It's hard to compare several decades of development of rare earth magnets with something which has only had a few years to develop. However, the energy product is already comparable (better) than rare earths.

NdFeB magnets are known to have fairly low Curie temperatures (operating temperatures). Does this new magnetic nanoparticle material negate this problem?

The curie temperature of NdFeB is around 320°C. The corresponding temperature in nanoparticles is 517°C.

What applications are likely to benefit from this new material?

Clean energy applications have the potential to benefit the most from these new materials. Right now, much of the research into more efficient, smaller electric motors was hampered due to the price fluctuations of rare earth elements. This new material offers a magnet which is made in a low cost green manner with readily available base metals like iron and cobalt.

Video Courtesy of Nanofoundry YouTube channel

What major steps are involved in the commercialization of the material for these applications?

Right now, the technology has been licensed to a Ashland, VA based spin-off Nanofoundry LLC. Nanofoundry has a phase two SBIR grant from the National Science Foundation to transition this new material from VCU laboratories. In addition, Nanofoundry is now working with large chemical companies in order to scale-up production and commercialize this new material.

Other Work

In 2013, Dr. Khanna and a team of scientists at Virginia Commonwealth University (VCU) in collaboration with scientists from John Hopkins University, synthesized magnetic superatoms.

A group at VCU previously predicted the existence of these magnetic superatoms in a paper which appeared in Nature Chemistry.

Superatoms have the ability to imitate various elements in the periodic table and are the potential building blocks for many nanomaterials. These nanomaterials may one day be used to develop molecular electronic devices for next generation memory storage.