Better Electric Motors to Arrive? Scientists Discovered New Magnetic Properties in Iron

Scientists at the Department of Energy’s Ames Laboratory have discovered rare-earth-like magnetic properties in iron under some special circumstances, which might spare the industry of using scarce natural magnetic ore to create electric motors and generators.
lithium iron nitride crystal 1 photo
Photo: DOE/Ames Laboratory
The electric motors in hybrid cars or EVs are using electromagnets and permanent magnets to transform electricity into mechanical movement. The electromagnet is simply a coil through which an electric current is passing so nothing too hard to get here. But the ‘permanent’ magnet has a different story.

The term ‘permanent magnet’ which is used in the industry now might lead you think its some sort of ore naturally being spawned in the Earth’s crust. Well, it’s a bit wrong, because unlike the real magnets (magnetite/lodestone), they are man made and are basically chunks of iron that have been specially treated in order to have a stable magnetic field.

In common industry magnets, iron gives them their strength and it also comes with the benefits of being cheap and abundant. But it still needs rare earth elements (natural magnets) to be transformed into a magnet. Iron is heated above its Curie temperature, after which is cooled in a magnetic field, so that its molecular structure will align in the right shape and create a strong magnetic force.

As you might have concluded, the challenge here is the actual rare-earth minerals which are expensive and are not found in large quantities to meet the demand.

However, scientists have recently discovered that iron can be magnetized using nitrogen. It’s still a delicate process which involves a mix of lithium and lithium-nitrate to create a solution in which iron can be dissolved.

"Usually iron and lithium don't mix," said Ames Laboratory physicist Paul Canfield. "It seems adding nitrogen to the lithium in the solution allows iron to go in."

The resulting crystals of iron-substituted lithium nitride not only act as a natural magnet but they were also more stable to reverse magnetization than current industry magnets.

"With detailed measurements, we saw that these single iron ions are indeed behaving like a single rare-earth ion would," Canfield continued. "And we believe this has to do with the special, fairly simple, geometry that the iron finds itself in: one iron atom positioned between two nitrogen atoms.”

Scientists hope the new crystal growing technique and the new magnet type will aid the industry by replacing the need for rare elements, which will impact electric motors and generators, as well as data storage and manipulation in quantum computer applications.

via ScienceDaily
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