Supercomputers Help Researchers Find Two New Kinds Of Magnets (phys.org)

"Predicting magnets is a heck of a job, and their discovery is very rare," said a mechanical engineering professor at Duke University. But after years of work synthesizing various predictions, material scientists "predicted and built two new magnetic materials, atom-by-atom, using high-throughput computational models." An anonymous reader quotes Phys.org: The success marks a new era for the large-scale design of new magnetic materials at unprecedented speed. Although magnets abound in everyday life, they are actually rarities -- only about 5% of known inorganic compounds show even a hint of magnetism. And of those, just a few dozen are useful in real-world applications because of variability in properties such as effective temperature range and magnetic permanence...

In a new study, materials scientists from Duke University provide a shortcut in this process. They show the capability to predict magnetism in new materials through computer models that can screen hundreds of thousands of candidates in short order. And, to prove it works, they've created two magnetic materials that have never been seen before.
"The first alloy is particularly interesting," reports the International Business Times, "because it contains no rare-earth materials, which are both expensive and difficult to acquire." But a Duke mechanical engineering professor points out that "It doesn't really matter if either of these new magnets proves useful in the future. The ability to rapidly predict their existence is a major coup and will be invaluable to materials scientists moving forward."

Comments

Which supercomputer?

[ShanghaiBill]

TFA seems to leave out a lot of important geeky details. Like which supercomputer was used? How many hours of CPU (or maybe GPU?) time was used? Since they were running hundreds of models in parallel, why did they need a supercomputer at all? Wouldn't it have been more cost effective to rent compute servers in the cloud?

Re:Which supercomputer?

[Dr. Spork]

Alnico magnets are awesome as pole pieces in pickups for electric guitars and basses. This year I started winding my own bass pickups, after testing many commercial pickups to get a sense of how the physical parameters affect tone. I can tell you that the kind of magnet you use makes an obvious difference to the sound of the instrument. It's not just about the net strength and geometry of the fields. Alnico magnets - but not ceramic, nor Nd - get eddy currents induced inside them from the vibrating strings, and this affects how they sound. I wonder whether Co2MnTi would also have these. I get the impression it's not a proper homogeneous alloy, so maybe not. Still, more info and a comparison field strengths would be useful. To a musician, a new type of magnet might be something like a newly discovered species of aromatic fruit: You immediately wonder what new aesthetic experiences it would allow for.

Re:Question for the Physicists.

[poodlediagram]

A permanent magnet is polarized by something called the exchange field. This is related to the Pauli exclusion principle and the Coulomb interaction and happens spontaneously. Energy is stored in the electronic state as kinetic, external and interaction (this includes the magnetic dipole field energy)

These two new magnets are unlikely to replace the current champion (neodymium-iron-boron), or be particularly useful as permanent magnets at all. The reason is that the researchers only calculated the moment and Curie temperature. A good permanent magnet should also have a high magnetic anisotropy energy (MAE) as well. The Heusler alloys are predominantly cubic and so have a very low MAE.

How do I know this? We just spent three years doing exactly the same thing: spending thousands of CPU hours trying to find a good magnet among the Heuslers. All to no avail.