Atom-by-atom: Scientists create two brand new magnetic materials

The process of creation of magnets is more of a hit-and-miss endeavor than an exacting science. However a new research published in 'Science Advance' reveals the creation of two brand new magnetic materials.

According to researchers at Duke University (DU), only about five percent of all known inorganic compounds exhibit a little magnetism. So instead of searching the world for new magnets, researchers took to computer modelling techniques to build two new types of magnets, atom-by-atom.

Specifically, they worked with a computational model that let them try out different molecules in different arrangements for a class of materials called Heusler alloys, which consist of three different elements arranged in particular ways. Considering the range of possible elements (55) and atomic structures, the potential compounds numbered 236,115.

That's a huge improvement over the traditional trial-and-error methods currently used by scientists, according to the team from Duke University, and could lead to the rapid discovery of new magnets for all kinds of purposes, from medical devices to car engines.

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Stefano Curtarolo from the Centre for Materials Genomics at Duke said, "Predicting magnets is a heck of a job and their discovery is very rare. Even with our screening process, it took years of work to synthesise our predictions."

By using computer models of potential prototypes – which calculated how atoms might interact, and the energy that would be required – the list was quickly cut down.

The models were also able to look for magnetic moments in each compound, or how they would react to external magnetic fields.

Finally, scientists were left with 14 candidates for new materials that they could then work on synthesising in the lab: of four that were chosen, two were eventually developed over the course of several years.

Although the synthesising process is still relatively slow, working on a handful of potential compounds is easier than trying to find the right combination in a group of 236,115, which is why the computer modelling technique could be so useful.

"There can be all types of constraints or special conditions that are required for a material to stabilise", explains one of the team, Corey Oses. "But choosing from 14 is a lot better than 200,000."

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The first new material, Co2MnTi, consists of cobalt, manganese, and titanium, and researchers were able to accurately predict the new magnet's properties, including the Curie temperature (the point when the material loses its magnetism).

That temperature turned out to be 938 Kelvin (1,228 degrees Fahrenheit), very close to the predicted 940 Kelvin (1,232 degrees Fahrenheit), making the material potentially useful in many commercial applications.

The second magnetic material, Mn2PtPd, mixes manganese, platinum, and palladium, and although it doesn't actually produce a magnetic field of its own, it has electrons that react strongly to magnetic fields. This would make it a good candidate for use in hard drives although, beyond that, its use is somewhat limited because its behavior is difficult to predict.

"It doesn't really matter if either of these new magnets proves useful in the future," says Curtarolo. "The ability to rapidly predict their existence is a major coup and will be invaluable to materials scientists moving forward."