Researchers create atom-thick alloys with unanticipated magnetic properties

October 11, 2017
A high-angle annular dark-field image of pure rhenium diselenide. In the key at bottom right, rhenium atoms are blue and selenium atoms yellow. Credit: Oak Ridge National Laboratory

Substituting atoms in the process of making two-dimensional alloys not only allows them to be customized for applications but also can make them magnetic, according to Rice University scientists and their collaborators.

A new paper in Advanced Materials outlines how researchers at Rice, Oak Ridge National Laboratory, the University of Southern California (USC) and Kumamoto University in Japan used (CVD) to make atom-thick sheets and, in the same step, tailor their properties by adding other elements through a process known as doping.

They discovered by surprise that they could also give the 2-D sheets magnetic properties.

The labs worked with , alloys that combine a transition metal and chalcogen atoms into a single material. Transition metals are stable elements that fall in the middle of the periodic table. Chalcogens include sulfur, selenium and tellurium, also neighbors to each other in the table.

By adding a dopant element to the mix during CVD, the researchers showed it was possible to rearrange the atoms on the resulting 2-D crystal sheets. They demonstrated several different configurations and found they could replace some atoms outright with the dopant. These physical changes led to changes in the mechanical and electronic properties of the flat crystals, said co-author and Rice postdoctoral researcher Chandra Sekhar Tiwary.

An image of rhenium-doped molybdenum diselenide shows how the material’s atomic structure has been rearranged by the addition. The key shows the positions of rhenium atoms in blue, selenium in yellow and molybdenum in red. Credit: Oak Ridge National Laboratory

The Rice lab of Pulickel Ajayan led the project to test theories by USC researchers who calculated that doping the would force a phase transition in the 2-D crystals. The Rice team confirmed the theory that adding rhenium in various amounts to molybdenum diselenide during growth would allow them to tailor its properties by changing its atomic structure. The magnetic signatures were a bonus.

"Usually, when you make a magnetic material, you start with magnetic elements like iron or cobalt," said graduate student and co-lead author Amey Apte. "Rhenium, in bulk, is not a , but it turns out it is in certain combinations at the atomic scale. It worked fantastically in this case."

The researchers said the they discovered could make the 2-D alloys of interest to those who design spintronic devices.

Explore further: Four elements make 2-D optical platform

More information: Vidya Kochat et al. Re Doping in 2D Transition Metal Dichalcogenides as a New Route to Tailor Structural Phases and Induced Magnetism, Advanced Materials (2017). DOI: 10.1002/adma.201703754

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KBK
not rated yet Oct 11, 2017
Claims made about montaomic gold or 'the food of the gods', or 'the white powder of gold', is that in it's final 'cooper paired' monatomic powder state..is that it is magnetic. One can even find videos about this, showing the magnetism. However, one could not prove provenance of the videos, so skepticism would abound upon viewing.

Secondly, claims that it bonds to dna and electrifies, polarizes, and aids DNA integrity to a very high degree. Providing a form of immorality to the body.

Modern science makes DNA markers with very fine gold particles -drug delivery, bonding and aiding system. So we know that this DNA claim is also not so crazy and has potential in known science.

Over time, each of the claims about this ancient 'food of the gods' is being found to be true.

What does that portend for the rest of the claims, which are: Superconductivity, immortality, and multidimensional consciousness?

We're over half way there in proving the claimed science of it....
Sonhouse
5 / 5 (1) Oct 11, 2017
Good luck with that.
Whydening Gyre
5 / 5 (2) Oct 11, 2017
Claims made about montaomic gold or 'the food of the gods', or 'the white powder of gold', is that in it's final 'cooper paired' monatomic powder state..is that it is magnetic. One can even find videos about this, showing the magnetism. However, one could not prove provenance of the videos, so skepticism would abound upon viewing.

Secondly, claims that it bonds to dna and electrifies, polarizes, and aids DNA integrity to a very high degree. Providing a form of immorality to the body.

Gold and DNA contribute to immorality...?
And here I thought it was wine, women and rock n roll....
PPihkala
not rated yet Oct 12, 2017
Claims made about montaomic gold or 'the food of the gods', or 'the white powder of gold', is that in it's final 'cooper paired' monatomic powder state..is that it is magnetic. One can even find videos about this, showing the magnetism. However, one could not prove provenance of the videos, so skepticism would abound upon viewing.

It did not take lot of searching to notice that most available monatomic gold is gold chloride, which is neurotoxic, so one might want to reconsider before consuming any.

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