Scientists discover novel type of magnetic wave

November 10, 2010

A team of international researchers led by physicists in the University of Minnesota's College of Science and Engineering have made a significant breakthrough in an effort to understand the phenomenon of high-temperature superconductivity in complex copper-oxides—one of the most studied scientific topics in history.

The University of Minnesota researchers and their international colleagues from Germany, France and China report the discovery of a novel type of magnetic wave involving oxygen atoms. The new findings could have implications for improving superconducting electric wires used in national electrical grids.

The study by lead author Martin Greven, an associate professor in the university's School of Physics and Astronomy, is published in the Nov. 11 issue of Nature together with a "News and Views" introduction. The research is also scheduled to be highlighted in the journal Science.

"Following the Nobel-Prize winning discovery of high-temperature in complex copper-oxide in the mid 1980s, the effort to understand this has been one of the major scientific challenges in the field of physics for the past quarter century, with more than 100,000 publications on the topic," Greven said.

"While the commercialization of these complex copper-oxide materials, in the form of superior electric wires, has recently begun, have not yet been able to solve the mystery of why these exotic materials are superconducting in the first place. The materials' unusual magnetism is often argued to be responsible for their superconductivity," Greven added.

In their experiments, the researchers bombarded the copper-oxide crystals with intense beams of neutrons. The neutrons themselves are magnetic, and by carefully measuring how these particles are scattered from the crystals, the research team was able to show the existence of unusual magnetic waves involving oxygen atoms.

"We believe that our discovery sheds new light on this hotly debated subject of superconductivity," Greven said.

Explore further: PhD student solves decade-long mystery of magnetism

More information: … ull/nature09477.html

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4.8 / 5 (16) Nov 10, 2010
"'We believe that our discovery sheds new light on this hotly debated subject of superconductivity,' Greven said."

Please, don't tell us what it is, let us guess! It is so much more fun that way!
1 / 5 (5) Nov 11, 2010
follow the links,search the web,you don't expect this site to spoon feed you,do you?
4 / 5 (4) Nov 11, 2010
I have to agree with fmfbrestel. The Nature link links to a summary, which refers to "an unusual magnetic order." Without a Nature subscription, readers have no idea what the "unusual magnetic order" might be. Sounds quite interesting, but this is less information than most Phys Org articles provide. Is there an arxiv ref?
3 / 5 (6) Nov 11, 2010
I agree with fmfbrestel. If we always have to search the web and follows the links we might as well not visit this site at all. Why bother?
4 / 5 (4) Nov 11, 2010
Took my own advice. It's easy to find in Arxiv. Go to Arxiv, click on condensed matter: superconductivity, and then use a search term comprised of: hidden magnetic excitation. Short article, but even so it is hard to provide a simple summary. I'll try: magnetic excitation branch...not the hourglass type...a long lived mode...present throughout the 2D Brillouin zone...fundamental collective mode...cannot be understood with conventional Hubbard models...requires instead an extended multi band approach. This hitherto unobserved excitation is a new candidate for the mysterious electron-boson interaction features previously observed with many techniques.

There you have it. I hope my rough summary does it justice.
5 / 5 (1) Nov 11, 2010
what a cliffhanger...
1 / 5 (4) Nov 11, 2010
IMO this stuff is known already and described with Colin Humphreys theory of superconductivity. He argues that each copper-oxide plane consists of square "nanodomains", separated by channels that are one unit-cell wide - rather like a grid of streets surrounding blocks of houses. Holes at the edges of adjacent blocks are magnetically paired and superconductivity occurs because these hole-pairs march collectively along the channels, like trams on pairs of tramlines running between the blocks of houses. There is one hole on each tramline, according to the model, and the pairs of holes move down the channels, hopping from oxygen to oxygen via adjacent copper sites.
1 / 5 (4) Nov 11, 2010
Annulus, to be read on my 'renewed' website.
not rated yet Nov 11, 2010
"The materials' unusual magnetism is often argued to be responsible for their superconductivity."



It's a tightness, or density/connectivity thing. Less electrostatic and more current oriented due to the below situation.

The odd seeming magnetic considerations are a result of electron orbital alignment, rotation and polarization. (pairing of outer orbitals of the differing oxides and materials)

Which when the right oxide pairing takes place, this results in a more seamless electron exchange or agreeable frequency relationship between the two materials (NMR frequency, ie, extremely and specific).

This results in high(er) temperature superconductivity.
not rated yet Nov 11, 2010
OK, I read about half the paper so far. It seems they know what I'm saying to some degree but they have yet to make the intellectual leap to the next needed area of thinking....

But... I never said how to fix it, but only where to look. :p.
1.2 / 5 (17) Nov 11, 2010
This results in high(er) temperature superconductivity.
I do believe, the mutual compression of electrons is the primary reason of even low-tempearature superconductivity. The presence of Cooper pairs is just a byproduct of it - anyway, it doesn't explain, why elements like sodium are never becoming superconductive, whereas gold does.

Just try to imagine it - sodium is soft metal with only repulsive spherical orbitals full of electrons on its surface. Whereas the gold atoms exhibit both spherical s-orbitals orbitals (which are providing its conductivity), both elongated d-orbitals, which are serving like glue of atoms, which exerts pressure against s-orbitals like 3D cage. Without sufficiently strong attractive bonds between atoms the superconductivity never appears.
1.2 / 5 (17) Nov 11, 2010
Of course, the mutual equilibrium of attractive and repulsive forces between various orbitals inside of individual atoms can never become so pronounced, like at the case of large molecular structures, mediated with molecular orbitals. The cage made of attractive atoms can become a much more robust, then the cage of individual d-orbitals. The pressure exerted with such cage to electron fluid could be a much higher there, because many attractive bonds are involved in the later case. Under such circumstances the Cooper pairs of electrons will condense further and they will change into pairs of electron "tramlines", which were predicted with Humphreys theory and depicted on the picture bellow.

In this way, the Cooper pairs based theories (BCS) are keeping their bit of truth in high-temperature superconductivity, but the Cooper pair formation accounts only with subtle portion to the total superconductivity.
5 / 5 (1) Nov 12, 2010
If this is true then it can mean only one thing. Oxygen added copper speaker cable will be appearing in stores throughout the land.

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