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In a breakthrough new study, scientists and engineers at the University of Minnesota have electrically transformed the abundant and low-cost non-magnetic material iron sulfide, also known as "fool's gold" or pyrite, into a magnetic material.
This is the first time scientists have ever electrically transformed an entirely non-magnetic material into a magnetic one, and it could be the first step in creating valuable new magnetic materials for more energy-efficient computer memory devices.
The research is published in Science Advances, a peer-reviewed scientific journal published by the American Association for the Advancement of Science (AAAS).
"Most people knowledgeable in magnetism would probably say it was impossible to electrically transform a non-magnetic material into a magnetic one. When we looked a little deeper, however, we saw a potential route, and made it happen," said Chris Leighton, the lead researcher on the study and a University of Minnesota Distinguished McKnight University Professor in the Department of Chemical Engineering and Materials Science.
[...] "We were pretty surprised it worked," Leighton said. "By applying the voltage, we essentially pour electrons into the material. It turns out that if you get high enough concentrations of electrons, the material wants to spontaneously become ferromagnetic, which we were able to understand with theory. This has lots of potential. Having done it with iron sulfide, we guess we can do it with other materials as well."
Leighton said they would never have imagined trying this approach if it wasn't for his team's research studying iron sulfide for solar cells and the work on magnetoionics.
"It was the perfect convergence of two areas of research," he said.
Leighton said the next step is to continue research to replicate the process at higher temperatures, which the team's preliminary data suggest should certainly be possible. They also hope to try the process with other materials and to demonstrate potential for real devices.
Journal Reference:
Jeff Walter, Bryan Voigt, Ezra Day-Roberts, et al. Voltage-induced ferromagnetism in a diamagnet [open], Science Advances (DOI: 10.1126/sciadv.abb7721)
(Score: 0) by Anonymous Coward on Tuesday August 04 2020, @07:56PM (6 children)
This still doesn't really change the fact that they didn't really do anything impressive.
"if you get high enough concentrations of electrons, the material wants to spontaneously become ferromagnetic,"
The part I didn't understand was that it didn't turn it into a permanent magnet. They didn't really do anything impressive. They just showed that with some things that are hard to magnetize with 'more power' you can still magnetize them.
(Score: 2) by ChrisMaple on Wednesday August 05 2020, @01:35AM (5 children)
It's more than that. Dig down into the citations, and you'll find that this only works up to 25 Kelvin.
More importantly, this is an advance in theoretical physics, something new and unexpected. Better yet, they're actually able to make the experimental results match some model.
(Score: 0) by Anonymous Coward on Wednesday August 05 2020, @05:08AM (4 children)
"something new and unexpected."
They found out that Iron Sulfide has a magnetic acceptability, something I could have found out from Wikipedia.
Magnetic susceptibility (χ) +1074·10−6 cm3/mol
https://en.wikipedia.org/wiki/Iron(II)_sulfide [wikipedia.org]
"they're actually able to make the experimental results match some model."
So it wasn't unexpected then. It was just another experiment with expected results. Those results were expected based on models from prior experiments. Big deal.
(Score: 0) by Anonymous Coward on Wednesday August 05 2020, @05:10AM
magnetic susceptibility *
(Score: 0) by Anonymous Coward on Wednesday August 05 2020, @06:09AM (2 children)
FeS != FeS2
Iron(II) sulfide != Iron(II) Disulfide
(Score: 0) by Anonymous Coward on Wednesday August 05 2020, @12:30PM (1 child)
Fair enough. So I'm reading about FeS2 and it says it's paramagnetic.
Pyrite
https://en.wikipedia.org/wiki/Pyrite [wikipedia.org]
So reading about paramagnetism it says
"Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field.
...paramagnets do not retain any magnetization in the absence of an externally applied magnetic field
When a magnetic field is applied, the dipoles will tend to align with the applied field, resulting in a net magnetic moment in the direction of the applied field."
https://en.wikipedia.org/wiki/Paramagnetism [wikipedia.org]
So ... it looks like the results of this experiment are ... what Wikipedia already says they will be?
(Score: 0) by Anonymous Coward on Wednesday August 05 2020, @08:52PM
No. Pyrite is paramagnetic because of the internal structure and impurities and the pure stuff should be weakly paramagnetic if not diamagnetic. Ferromagnetism is not the same as paramagnetism. When you apply electricity to this material, it generates its own ferromagnetic field temporarily. This is not the same as reacting to an externally applied magnetic field as a paramagnetic or ferrimagnetic material.