Main Attraction: Scientists Create World’s Thinnest Magnet – Just One Atom Thick!
A one-atom-thin 2D magnet developed by Berkeley Lab and UC Berkeley could advance new applications in computing and electronics.
[...] The researchers synthesized the new 2D magnet – called a cobalt-doped van der Waals zinc-oxide magnet – from a solution of graphene oxide, zinc, and cobalt.
Just a few hours of baking in a conventional lab oven transformed the mixture into a single atomic layer of zinc-oxide with a smattering of cobalt atoms sandwiched between layers of graphene.
In a final step, the graphene is burned away, leaving behind just a single atomic layer of cobalt-doped zinc-oxide.
[...] To confirm that the resulting 2D film is just one atom thick, Yao and his team conducted scanning electron microscopy experiments at Berkeley Lab’s Molecular Foundry to identify the material’s morphology, and transmission electron microscopy (TEM) imaging to probe the material atom by atom.
X-ray experiments at Berkeley Lab’s Advanced Light Source characterized the 2D material’s magnetic parameters under high temperature.
Additional X-ray experiments at SLAC National Accelerator Laboratory’s Stanford Synchrotron Radiation Lightsource verified the electronic and crystal structures of the synthesized 2D magnets. And at Argonne National Laboratory’s Center for Nanoscale Materials, the researchers employed TEM to image the 2D material’s crystal structure and chemical composition.
The researchers found that the graphene-zinc-oxide system becomes weakly magnetic with a 5-6% concentration of cobalt atoms. Increasing the concentration of cobalt atoms to about 12% results in a very strong magnet.
To their surprise, a concentration of cobalt atoms exceeding 15% shifts the 2D magnet into an exotic quantum state of “frustration,” whereby different magnetic states within the 2D system are in competition with each other.
And unlike previous 2D magnets, which lose their magnetism at room temperature or above, the researchers found that the new 2D magnet not only works at room temperature but also at 100 degrees Celsius (212 degrees Fahrenheit).
“Our 2D magnetic system shows a distinct mechanism compared to previous 2D magnets,” said Chen. “And we think this unique mechanism is due to the free electrons in zinc oxide.”
[...] According to Chen, zinc oxide’s free electrons could act as an intermediary that ensures the magnetic cobalt atoms in the new 2D device continue pointing in the same direction – and thus stay magnetic – even when the host, in this case the semiconductor zinc oxide, is a nonmagnetic material.
“Free electrons are constituents of electric currents. They move in the same direction to conduct electricity,” Yao added, comparing the movement of free electrons in metals and semiconductors to the flow of water molecules in a stream of water.
Journal Reference:
Rui Chen, Fuchuan Luo, Yuzi Liu, et al. Tunable room-temperature ferromagnetism in Co-doped two-dimensional van der Waals ZnO [open], Nature Communications (DOI: 10.1038/s41467-021-24247-w)
(Score: 0, Offtopic) by Anonymous Coward on Tuesday July 27 2021, @01:35AM
American atom, no? That's prety damn thick, equivalent to dozen Ethiopean atoms.
(Score: 3, Interesting) by JustNiz on Tuesday July 27 2021, @01:50PM (2 children)
2D implies that it has ZERO size in one dimension. This is absolutely not true. The smallest dimension is at least one atom thick.
(Score: 2) by Freeman on Tuesday July 27 2021, @02:59PM
What about when you're measuring the constituent parts of an atom?
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 1, Informative) by Anonymous Coward on Wednesday July 28 2021, @01:02AM
In materials science, 2D implies that there are no significant interactions in the direction perpendicular to the plane of the materials. So physicists will keep, rightly, using the descriptor 2D, and you can stuff it in your sock if you don't like it.