Argonne scientists discover new class of glassy material

Jul 28, 2008
The red arrows show the directions that the magnetic moments would point if dynamic frustration did not prevent them from ordering the crystal structure of PrAu2Si2, which is a spin glass below 3 Kelvin. Image: ANL

(PhysOrg.com) -- Scientists at U.S. Department of Energy's Argonne National Laboratory are dealing with an entirely new type of frustration, but it's not stressing them out.

Dynamic frustration has been found to be the cause of glassy behavior in materials that previously had none of the features of a normal glass.

"This has been a puzzle for 10 years now," Argonne physicist Raymond Osborn said.

Conventional wisdom states that glassy materials, such as common window glass, result when frustration prevents the atoms from forming a well-ordered crystal structure, and the material freezes into a disordered state like a frozen liquid.

In spin glasses, it is the magnetic moments on each atom, rather than the atoms themselves, that freeze into a disordered state at low temperatures, so that they point in random directions. However, there has to be some disorder in the atomic structure and some frustration in the magnetic interactions which prevents the magnetic moments from ordering so that they can freeze into spin glasses.

Scientists have struggled for more than a decade to understand why PrAu2Si2 is a spin glass. There is no sign of atomic disorder in the compound and, no reason for the magnetic interactions to be frustrated.

Using the results of neutron scattering experiments, Osborn and his collaborators concluded the frustration results from temporal or dynamic frustration rather static frustration.

Although PrAu2Si2 seems to have an ordered structure, by delving deeper, Osborn found that the magnetic moments are continually fluctuating in magnitude causing the equivalent of temporal potholes that appear and then disappear long enough to disrupt the magnetic alignment.

These fluctuations occur because the magnetic moments in this material are unstable and can be destroyed temporarily by electrons scattering off the atoms.

"The discovery of dynamic frustration reveals a whole new class of glassy materials whose behavior is governed by dynamic rather than static disorder," Osborn said.

This discovery may allow scientists to tune the degree of frustration and therefore develop a better understanding of how glasses are formed in nature.

A paper on Osborn's work can be seen in the upcoming edition of Nature Physics.

Source: Argonne National Laboratory

Explore further: Pseudoparticles travel through photoactive material

Related Stories

Recommended for you

Pseudoparticles travel through photoactive material

Apr 23, 2015

Researchers of Karlsruhe Institute of Technology (KIT) have unveiled an important step in the conversion of light into storable energy: Together with scientists of the Fritz Haber Institute in Berlin and ...

From metal to insulator and back again

Apr 22, 2015

New work from Carnegie's Russell Hemley and Ivan Naumov hones in on the physics underlying the recently discovered fact that some metals stop being metallic under pressure. Their work is published in Physical Re ...

Electron spin brings order to high entropy alloys

Apr 22, 2015

Researchers from North Carolina State University have discovered that electron spin brings a previously unknown degree of order to the high entropy alloy nickel iron chromium cobalt (NiFeCrCo) - and may play ...

Expanding the reach of metallic glass

Apr 22, 2015

Metallic glass, a class of materials that offers both pliability and strength, is poised for a friendly takeover of the chemical landscape.

Electrons move like light in three-dimensional solid

Apr 22, 2015

Electrons were observed to travel in a solid at an unusually high velocity, which remained the same independent of the electron energy. This anomalous light-like behavior is found in special two-dimensional ...

Quantum model helps solve mysteries of water

Apr 20, 2015

Water is one of the most common and extensively studied substances on earth. It is vital for all known forms of life but its unique behaviour has yet to be explained in terms of the properties of individual ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

thales
5 / 5 (3) Jul 28, 2008
Learning how to prevent crystallization would have a huge impact on cryonics. I'm excited for this line of research.
jeffsaunders
3 / 5 (2) Jul 28, 2008
I'm excited - controlled chaos may lend itself to use in many fields including electronics.
mrlewish
4 / 5 (1) Jul 29, 2008
Odd question. So if I were to cool down some transparent glass enough it would stop transmitting light? I mean no energy would equal an ordered state.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.