Interesting news out of Duke University, where new magnets are now being built in a laboratory, atom by atom. While production on a mass scale at a reasonable cost is still many years away, this could be the first step toward a magnet creation process that would be more immune to severe market disruption.
The rare earth materials used in permanent magnets have been subjected to price changes and supply issues for more than a decade. This is particularly problematic at a time when rare earth metals are more in demand than ever, for use in everything from hybrid cars to wind turbines to MRI machines.
The most abundant sources of rare earth elements are in Africa, Australia, and China, but these supplies have been threatened at various times by political and economic disputes that have affected both price and availability.
Alternative Sources for Permanent Magnets
That market uncertainty has inspired the search for new ways to assure adequate supply. One national laboratory designed a patented process to recover rare earth magnets from used hard drives. These magnets can then be recycled into new computers, or resized and shaped for use in other consumer goods.
But Duke’s creation of new magnetic materials using high-throughput computational models could one day generate new molecular structures with remarkable magnetic properties.
One of the breakthroughs of the Duke experiments was a computer model that significantly boosts a scientist’s ability to predict magnetism in new materials, and to create such materials where none previously existed.
The study focused on Heusler alloys, which are materials made with atoms from three or more elements that are arranged in one of three distinct structures. This produced more than 230,000 combinations, but through a computer model that assessed how the atoms would react, the field of possibilities was trimmed to about 35,000. Further research lowered that number to below 250, and then down to just 14 that were considered strong enough possibilities for actual synthesis.
While the prospects are exciting, keep in mind that it took years to arrive at the first set of screening predictions, and several more years to actually create the new materials in a lab from cobalt, magnesium, and titanium.
And magnetic properties are not enough – any newly created materials must be able to withstand challenging industrial conditions, such as extreme temperatures, to which they may be exposed.
Although probably not of commercial interest, one of the new magnets made from manganese, platinum and palladium (Mn2PtPd) is actually an antiferromagnet, which has no internal magnetic moment of its own, though it still makes electrons responsive to external magnetic fields. That means it could be adaptable for use in small electronic devices, although it’s probably not suitable for large, common magnet applications.
First steps are just that – they take new ideas and test them online and in the real world, to learn what works and what doesn’t, and then refine the process until it becomes something with marketable potential. At Duke University, they have just taken a very intriguing first step.
