Roller coaster superconductivity discovered

Aug 18, 2010
This graphic shows the crystal structure of three-layered bismuth oxide. Credit: Xiao-Jia Chen

Superconductors are more than 150 times more efficient at carrying electricity than copper wires. However, to attain the superconducting state, these materials have to be cooled below an extremely low, so-called transition temperature, at which point normal electrical resistance disappears. Developing superconductors with higher transition temperatures is one of physics' greatest quests.

Until now, copper-laden materials called cuprates have been the only superconductors whose transition temperatures are higher than the liquid nitrogen boiling point at -321F (77 K). Whether researchers can make transition temperatures higher in such materials remains a challenge.

Now, researchers at the Carnegie Institution's Geophysical Laboratory, with colleagues, have unexpectedly found that the transition temperature can be induced under two different intense pressures in a three-layered bismuth oxide crystal referred to as "Bi2223." The higher produces the higher transition temperature. They believe this unusual two-step phenomena comes from competition of electronic behavior in different kinds of copper-oxygen layers in the crystal. The work is published in the August 19, 2010, issue of Nature.

"Bi2223 is like a layered cake," explained lead author Xiao-Jia Chen at Carnegie. "On the top and bottom there are insulating bismuth-oxide layers. On the inside of those, come layers of strontium oxide. Next, are layers of , then calcium, and finally the middle is another copper-oxide layer. Interestingly, the outermost and inner layers of copper oxide have different physical properties resulting in an imbalance of electric charge between the layers."

One way scientists have found to increase the transition temperature of is to "dope" them by adding charged particles.

Under normal pressure, the optimally doped Bi2223's transition temperature is -265F (108K). The scientists subjected doped crystals of the material to a range of pressures up to 359,000 times the atmospheric pressure at sea level (36.4 Giga Pascal), the highest pressure yet for magnetic measurements in cuprate superconductors. The first higher transition temperature happened at 100,666 atmospheres (10.2 GPa).

"After that, increasing pressures ended up with lower transition temperatures," remarked Chen. "Then to our complete surprise at about 237,000 atmospheres (24 GPa) the reappeared. Under even more pressure, 359,000 atmospheres, the transition temperature rose to -215F (136K). That was the highest pressure our measuring system could detect."

Other research has shown that some multilayered superconducting materials like this one exhibit different electronic and vibrational behaviors in different layers. The researchers think that 237,000 atmospheres might be a critical point where pressure suppresses one behavior and enhances superconductivity.

"The finding gives new perspectives on making higher in multilayer cuprate superconductors. The research may offer a promising way of designing and engineering with much higher transition temperatures at ambient conditions," concluded coauthor Viktor Struzhkin also of Carnegie.

Explore further: Impurity size affects performance of emerging superconductive material

Provided by Carnegie Institution

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robbor
1 / 5 (3) Aug 18, 2010
what happened to carbon nanotubes?
KronosDeret
1 / 5 (3) Aug 19, 2010
simply put too many lines of research, i'm just waiting who will take the pole first. Im betting on graphen electronics, quantum dot optics and photovoltaics. But there are so many more possibilities.
Macksb
1 / 5 (2) Aug 19, 2010
Let me explain this result. It is consistent with a theory about superconductors that I have expressed in several sites, based on Art Winfree's law of coupled (synchronized) oscillators.

Pressure increases the proximity of atoms and particles and thus increases their tendency to synchronize via Winfree's law of coupled oscillators (which he applied to biology, not physics). However, pressure also restrains the movements of the oscillating components, which may in turn cross a limit and prevent the oscillators from synchronizing. In that case, higher temperatures might overcome that constraint. The increased temperature (energy) may increase the force of the oscillations enough to permit sufficient interaction among the oscillators so they synchronize in time and space. The spacial separation in tetragonal and orthorhombic superconductors, and some freedom of movement therein, is the image to keep in mind as you ponder my analysis. Superconductivity is Winfree synchrony.

Xaero
1.8 / 5 (5) Aug 21, 2010
superconductivity could be explained in easier way. Try to imagine, you're squeezing electrons through the thin pipe. Electrons are repulsing with neighboring atom (electrons) and because they're avoiding each other like obstacles, they will pass the tube in small jumps. During these jumps they will radiate some photons, thus dispersing the energy of their motion.

But what will happen, if you compress electrons inside of pipe very much? Every electron will be surrounded with many others and their repulsive forces will overlap and compensate mutually from all directions at the same moment. The portion of electrons would move freely inside of such superfluid.

BTW On the similar principle the bazooka weapon is based. High pressure wave liquefies the metal, so that the portion of explosive target can propagate through it at large distance.
Xaero
1.8 / 5 (5) Aug 21, 2010
Many polymers have bulky molecules, which repulse mutually due the water molecules attached at distance. Their compression liquefies them temporarily. So that the shaking of ketchup in the bottle is actually an attempt to induce liquefying effect in it. The superfluidity induced with pressure is called a supersolidity. The interior of large planets and/or neutron stars is believed superfluous, too.
Xaero
1.8 / 5 (5) Aug 21, 2010
Actually, if you think, you know about physics, you can add another example of liquefaction of matter under pressure. The very last proposal supported by link is the winning one....

For example, pressure sterilization is based on the liquefaction of membranes of microorganisms, which destroys complex tertiary structure of proteins.

http://www.food-f...rlin.pdf
Skeptic_Heretic
3 / 5 (4) Aug 22, 2010
For example, pressure sterilization is based on the liquefaction of membranes of microorganisms, which destroys complex tertiary structure of proteins.
Because osmotic pressure causes a differential in their membranes leading to implosion. It's no more liquefaction than a case of the bends for a scuba diver. Complete non-sequitor relating to your "theory" again
Xaero
1.8 / 5 (5) Aug 22, 2010
.. Because osmotic pressure causes a differential in their membranes leading to implosion....
Pressure sterilization has nothing to do with implosion of cells. Actually you just described the plasmolysis, which occurs, whenever cell is placed into concentrated solution of sugar or honey. This is why these solutions have a sterilization effect, too.

http://en.wikiped...smolysis

You're half educated senile troll, who is confusing and mixing various concepts together - which is apparent, whenever you open your mouth.
Skeptic_Heretic
3 / 5 (2) Aug 22, 2010
You're half educated senile troll, who is confusing and mixing various concepts together - which is apparent, whenever you open your mouth.
Actually no, both methods work in the same manner. One is effectively poisoning the other is crushing.

You may want to take it easy with the baseless insults when you have little to no understanding of the person you're speaking to.
Xaero
1.7 / 5 (6) Aug 22, 2010
both methods work in the same manner. One is effectively poisoning the other is crushing
Only in your fuzzy head. High pressure doesn't makes cells inflate - it actually dissolves them by disruption of their outer-membrane permeability.

http://aem.asm.or...6/9/3966

You actually never heard of high pressure sterilization, am I right? The senility is a medical term - I'm just describing the real state of your mind in objective way.
understanding of the person you're speaking to

Do you know, what is real problem with you? You're too lazy to search and provide links, supporting your stance. You're just believing, you're smart enough to replace the missing information at run time. If you would use a Google before starting your negativism, you could never get into such situations repeatedly, because you would have a relevant link prepared already. You're too arrogant and lazy at the same moment - and this is a deadly combination at internet discussions
Skeptic_Heretic
2.3 / 5 (3) Aug 22, 2010
Only in your fuzzy head. High pressure doesn't makes cells inflate - it actually dissolves them by disruption of their outer-membrane permeability.
I didn't say it makes them inflate, did I? Crushing isn't an explosion, well outside of fusion.
tihsgod
3.4 / 5 (7) Aug 22, 2010
Xaero, the personal abuse is pretty poor to read.I suggest you stick to the science because I can read this other stuff on five million other sites.
Xaero
1.7 / 5 (6) Aug 22, 2010
Look, now we are filling the thread by dozen completely redundant OT posts, just because you're too big troll for to recognize, how big troll you actually are.

High pressure sterilization doesn't makes cell inflate or implode. After all, if it would, it couldn't be used as one of the most careful treatment of sensitive food. After all, I'm not here for explanation the difference between pressure sterilization and osmosis or whatever else concept, randomly picked by senile troll from the net.

You got the link, educate yourself. If you're incapable of it - you know already, where to go...
Xaero
1.8 / 5 (5) Aug 22, 2010
Xaero, the personal abuse is pretty poor to read.
Dunning Krueger effect is a real effect and it applies to real people - it's a science. And I've no apologies for half-educated trolls, who label other crackpots without arguments.

http://en.wikiped...r_effect
Macksb
1 / 5 (3) Aug 22, 2010
The superconducting state emerges when the constituent atoms and particles are fully interconnected, and the interconnections lead to a highly ordered state, eliminating the frictions that normally impede the progress of a current. Art Winfree described the process--coupled oscillators, like Malaysian fireflies, or the gaits of a horse. But he developed it in biology (heart cells, etc.) not physics. It can and should be applied to physics--phase transitions generally, and specifically superconducting phase transitions and Bose-Einstein condensates. It is a fundamental theory of organization that fits comfortably within the laws of physics, including the four fundamental forces. The explanatory power of Winfree's theory, when extended to physics, suffices to explain Cooper pairs (orbits and spins both coupled, exactly antisynchronously), the boson requirement, pnictides, cuprates, and magnesium diboride, superfluidity, and BEC. Ockham's Razor says any theory that powerful wins.
Macksb
1 / 5 (3) Aug 22, 2010
Specifics:

1. Cooper pairs: orbit oscillations and spin oscillations both coupled, exactly antisynchronously. S wave symmetry (simple form). Lowest temp.

2. Pnictides. The Riken research (2010) shows that waves (aka oscillations) intersect perfectly if the angle is set just right. S wave symmetry (extended version). Somewhat higher temp.

3. Cuprates: D wave symmetry. And at the transition point, the four way clusters organize themselves at precise distances with respect to all the other clusters. Four way symmetry, internally and externally. Higher temp. Symmetry and fractal extensions thereof.

Why do these transitions happen? Think German history, for example. Hundreds of princes held power in the Middle Ages. Travel difficult, trade minor. Then trade increases, railways emerge and interconnect, common currency emerges. In short, interconnections expand dramatically. Bismarck mediates these changes into a nation. Or think warlords in China, then Sun Yat Sen, on to Mao.
Macksb
1 / 5 (3) Aug 22, 2010
4. Superfluidity--H 3 version (the surprising one, being a fermion). The Cooper pairs are atoms, not electrons. The mediator is spin oscillations, as opposed to phonons in BCS theory (phonons being wave oscillations, sound). The "mediation" is simply Winfree's law of coupled oscillators. Notice a similarity? Oscillations have a tendency to couple, especially when proximity of the oscillators increases, and the range of the oscillations increases--which happens when temperature is lower and the frequency of oscillation is thereby reduced. Similar to the long range communication between elephants, at frequencies so low they are inaudible to the human ear.

Temperature and pressure govern most phase transitions. Temperature = frequency of oscillation. Pressure = proximity of oscillators. If there is no latent heat, the oscillation in question is typically spin.

Now for some speculation. Higher temp superconductors, above the cuprates, will involve complex 8-way pairing.
Macksb
1 / 5 (3) Aug 22, 2010
5. Superinsulator.

Scientists at Argonne National have discovered a superinsulator state in a material that is a superconductor at other temperatures. See Nature, 2008, and PRL 2010. The theories on offer for superconductivity do not suggest anything like this. Yet this result fits perfectly within the Winfree law of coupled oscillators. Winfree proves that some systems of oscillators, such as a two oscillator system, will couple either synchronously or exactly antisynchronously. That is the Argonne result.

6. Fractional Quantum Hall Effect.

Same analysis: the fractions for fqHe are all implicit in the patterns described by Winfree as the allowable coupling patterns within systems of oscillators (configured in the manner that produces fqHe). Moreover, the exactness of the fqHe phenomenon, which understandably stuns Robert Laughlin and other experts, must be a case of perfect synchrony, where every oscillation in the system is synchronized with the others. No strays.
frajo
4 / 5 (3) Aug 23, 2010
The explanatory power of Winfree's theory, when extended to physics,
Where can I read about this theory?
hodzaa
1.8 / 5 (5) Aug 23, 2010
Such question has no meaning, as you can find the reference with using of Google easily. No connection to physical system of high Tc superconductors is given there, though.

http://carma.newc...apers/By Others/strogatz.pdf
Macksb
1 / 5 (2) Aug 23, 2010
The Winfree theory of coupled oscillators is described in an article by Strogatz and Stewart in Scientific American, December 1993. You can find the article easily on Steve Strogatz's web site at Cornell. Google Strogatz Cornell. It is about the third or fourth article in his list of publications. Click on that. Note especially the illustration on page 72, which is about the 4th or 5th page of the article. Focus on the waves in the illustration. See also Sync, the book by Strogatz.

True, Art Winfree applied his theory to bio only...not physics. But Mother Nature does not distinguish between the two disciplines. And I spoke to Art several times in the last two or three years before he died, asking whether his idea could be extended to physics. He said he believed so.

As applied by Winfree to bio, the idea is that oscillators synchronize in time, in certain exact patterns. Again, see page 72 for some patterns. In physics, synchrony is in organization of particles, atoms.
Macksb
1 / 5 (2) Aug 23, 2010
Art Winfree's theory is math, primarily--not bio. He developed the math and applied it to bio, but math applies stupendously well to physics, as we all know. And Art's math has been fruitful. In the 45 years since Art originated the math, it has been extended and further developed by many other mathematicians, such as Strogatz.

There are more than 110,000 papers on Arxiv about superconductivity, with no theory yet. Physicists may have exhausted their tool kit. In that light, the fact that physicists are largely unaware of Winfree's work is a reason to consider that work, not reject it. Winfree's theory knocks on our door: It is well grounded in math; identifies a new approach to organization of many bodies; applies throughout the natural (bio) world; and it shows how organization emerges from and is driven by oscillations. Condensed matter physics is rich with oscillations of all types.
frajo
1 / 5 (1) Aug 23, 2010
The Winfree theory of coupled oscillators is described in an article by Strogatz and Stewart in Scientific American, December 1993. You can find the article easily on Steve Strogatz's web site at Cornell.
Not really - the site gives an "internal server error". But I found that Strogatz is a mathematician working on complex networks and dynamical systems.

Unfortunately this doesn't help me to understand what "Winfree's theory of coupled oscillators" is about. I'm suspecting it's a misnomer, as the phenomenon of coupled oscillators is well known in physics since more than three centuries.
Macksb
1 / 5 (1) Aug 23, 2010
Frajo:

Not sure why there was a problem. I pulled it up minutes before making my post to be sure it still worked.

Regarding your three centuries comment, yes, the original idea can be traced to Christian Huygens and his two pendulum clocks. The pendula synced, to his amazement, in 1657, if memory serves. But Winfree contributed important new ideas in the 1960s, subsequently extended by Kuramoto in the 1980s, I believe.

I have made one adjustment. Winfree said, in effect, that oscillators (humans, horses, fireflies) adjust their oscillations. I reverse that, and say that in physics the oscillations organize their oscillators (which, when organized, are what we call phases of matter).

Another example is the relatively new "bosenova" phenomenon. The application of a specific external control (magnetism--spin) shrinks the rubidium cloud instantly; but when the oscillators are so shrunk, in close proximity, they cannot live together. Two Winfree patterns at work.
Xaero
1 / 5 (4) Aug 23, 2010
The theory is described here

http://tam.cornel...sync.pdf

I don't see any usage of it at the case of high Tc superconductivity. It's completely ad-hoced in this context.
Macksb
1 / 5 (1) Aug 23, 2010
Xaero:

Thanks for the link you provided in the preceding post. That's the right one.

Sincerely,

Macksb
Macksb
1 / 5 (1) Aug 23, 2010
Xaero:

Thanks also for you "ad hoc" challenge. Let's take BCS theory. Cooper pairs clearly involve synchronized oscillations--spin. The two half spins, organized antisynchronously, act as a boson. And what mechanism organizes those oscillations? More oscillations, in the form of phonons. BCS by its own terms is all about oscillations.

Recast in this light, BCS theory becomes much broader, and looks like Winfree's theory. It becomes logical to ask if the same oscillations, or other oscillations, might form pairs or synchronies in other patterns--perhaps more complex patterns. The evidence so far in pnictides and cuprates suggests yes--there are patterns and symmetries. These symmetries might be produced by synchronized oscillations, and the data suggest as much. The patterns seem to be somewhat more complex, and extended, than the simple Cooper pair model.

Two fermions will behave like a boson if their spin oscillations are coupled. One half and one half make one.
Xaero
1 / 5 (4) Aug 23, 2010
...These symmetries might be produced by synchronized oscillations, and the data suggest as much..
Well, we can presume, superconductive phase is formed with heavily compressed electrons, so that sort of synchronized oscillations may occur here. I just don't see any usage of it in testable predictions.

It brings me this famous joke on the mind:

http://i38.tinypi...i2og.png
Macksb
1 / 5 (1) Aug 23, 2010
Xaero:

Fun joke. As Brer Rabbit said, "Please don't throw me in that briar patch."

Macksb
Macksb
1 / 5 (1) Aug 26, 2010
Superconductivity has now been found in at least three ares--the traditional BCS materials, the cuprates, and the pnictides. Surely these three results must share some common theoretical explanation. That starting point, if correct, supports the views I have expressed above, which are based on a common theory, and one which fits the data in each case. Do others on this board oppose this single theory approach and wish to argue that three different theories are required? If so, I would like to see your comments.

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