New study advances quest for better superconducting materials

Jan 27, 2014
ORNL study advances quest for better superconducting materials
This is Minghu Pan's image of "clover-like" atomic defects -- an example is circled -- that result in strong superconductivity. Credit: ORNL

Nearly 30 years after the discovery of high-temperature superconductivity, many questions remain, but an Oak Ridge National Laboratory team is providing insight that could lead to better superconductors.

Their work, published in Physical Review Letters, examines the role of chemical dopants, which are essential to creating – materials that conduct electricity without resistance. The role of dopants in superconductors is particularly mysterious as they introduce non-uniformity and disorder into the crystal structure, which increases resistivity in non-superconducting materials.

By gaining a better understanding of how and why chemical dopants alter the behavior of the original (parent) material, scientists believe they can design superconductors that work at higher temperatures. This would make them more practical for real-world wire applications because it would lessen the extreme cooling required for conventional superconducting material. Existing "high-temperature " operate at temperatures in the range of negative 135 degrees Celsius and below.

"Through this work, we have created a framework that allows us to understand the interplay of superconductivity and inhomogeneity," said lead author Krzysztof Gofryk, a post-doctoral fellow in the Department of Energy laboratory's Materials Science and Technology Division. "Thus, for the first time we have a clearer picture of the side effects of dopants."

ORNL's Athena Safa-Sefat, who led the team, noted that while scientists have made progress since the first observation of superconductivity in the Dutch province of South Holland in 1911, they still do not know what causes some complex multicomponent materials to be superconductive at high temperatures. Additional progress will most likely hinge on answering fundamental questions regarding the interactions of atoms with the crystal, and this work represents a step forward.

"Our bulk and atomic-scale measurements on an iron-based superconductor have revealed that strong superconductivity comes from highly doped regions in the crystal where dopants are clustered," Sefat said. "If we can design a crystal where such clusters join in an organized manner, we can potentially produce a much higher performance superconductor."

While several companies manufacture superconducting materials that have been used in specialty applications and demonstration settings, widespread adoption is restricted by cost and complexity. An ideal superconducting wire would be constructed from inexpensive, earth-abundant non-toxic elements. It will also be low-cost for the manufacture of long lengths that are round and flexible and feature good mechanical – non-brittle – properties with a high superconducting temperature.

Explore further: Scientists create first computer-designed superconductor

More information: "Local inhomogeneity and filamentary superconductivity in Pr-doped CaFe2As2," Physical Review Letters, 2014.

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johanfprins
1.3 / 5 (4) Jan 28, 2014
The following quote is pathetic: "The role of dopants in superconductors is particularly mysterious "

I have already proved convincingly 10 years ago that the charge-carriers within ALL superconducting materials are localised electronic states whether they are intrinsic, as in the case of non-ideal metals (semi-metals) or are introduced by doping (i.e. are extrinsic). The mechanism is the SAME in all materials: Namely consecutive "tunnnelling" by one localised state to the next. ALL materials have been modelled by this SINGLE mechanism and the fits to experimental data are in all cases, compellingly correct.See http://www.cathod...nism.pdf

It is shocking that the mainstream physicists working on superconduction find the role of dopants "mysterious" ter it has already been known for more than10 years that the superconducting charge-carriers MUST be localised electronic states within all materials that superconduct.
Osteta
Jan 28, 2014
This comment has been removed by a moderator.
johanfprins
1 / 5 (2) Jan 28, 2014
@Osteta,

Zephyr! Why do you not read but only vomit the same nonsense over and over again. How does a dopant atom "sucks" electrons from outside? Your model sucks!
Osteta
Jan 28, 2014
This comment has been removed by a moderator.
johanfprins
1 / 5 (2) Jan 28, 2014
If what you state is correct, you should be able to fit your model quantitatively to published data. My model fits ALL data EVER published on superconductors. There is no proof that your "model" if one can call it that, can model anything quantitatively at all.

Note that quantitative does not mean a duck swimming in a pond while farting bubbles!
shavera
4.2 / 5 (5) Jan 28, 2014
ITT: Crackpot FIGHT!
johanfprins
1 / 5 (2) Jan 28, 2014
so if you have model that fits all data on superconduction, including those that cannot be modelled by "Cooper Pairs", then you are a crackpot? Not those people who want to believe at all cost in Cooper Pairs, even though the latter concept cannot explain all the data on superconduction as my model does?

My God! Who are the REAL crackpots in this saga? How pathetic can one become Shavera?
Nestle
1 / 5 (1) Jan 28, 2014
If what you state is correct, you should be able to fit your model quantitatively to published data. My model fits ALL data EVER published on superconductors
How your model differs from mine one? The quantitative agreement of theory isn't proof of its correctness, as proponents of epicycle model already know.
johanfprins
1 / 5 (1) Jan 29, 2014
If what you state is correct, you should be able to fit your model quantitatively to published data. My model fits ALL data EVER published on superconductors
How your model differs from mine one? The quantitative agreement of theory isn't proof of its correctness, as proponents of epicycle model already know.


You are correct that a quantitative agreement is sometimes obtained even when the physics on which it is based is wrong: For example epicycles, QFT etc.: However, if your hand-waving model cannot be applied to get quantitative agreement, it cannot be considered as being physics!.

Quantitative agreement, although it can be obtained for wrong physics, must be valid when the physics is correct. Thus any model that cannot give any quantitative fits to experimental data must be rejected until such a fit can be demonstrated. Your model cannot do this, and until it can, which I believe will be NEVER, it has to be rejected as falling outside the ambit of real physics.
Osteta
Jan 29, 2014
This comment has been removed by a moderator.
johanfprins
not rated yet Jan 29, 2014
The common people


Are you claiming that scientists who have to find superconductors and apply them are "common people"? That the present mainstream scientists who are presently working on superconduction are ALL certifiable morons, are as clear as daylight.

But this does not mean that they can ever really understand superconduction if they cannot use this knowledge to compute. In fact, if they cannot use this knowledge to compute, it proves convincingly that they do not really understand how it really works.

You are an example of this: You arrogantly believe that you understand how superconduction works even though it is totally impossible to use your "insights" to compute anything. This proves compellingly that you do not know how superconduction works. If you do, then compute and fit to experimental results. This is THE ONLY WAY in physics which has EVER worked in practice. Your hand-waving models based on ducks and bubbles contribute NOTHING to physics.

Osteta
Jan 29, 2014
This comment has been removed by a moderator.
Osteta
Jan 29, 2014
This comment has been removed by a moderator.
johanfprins
not rated yet Jan 29, 2014
If you're sure, I'm just wrong, then how your model of superconductivity differs from mine one? We can check the blind spots and differences of both models. Without it it's just a handwawing from your side.


There is no hand-waving from my side since my model is quantified and fitted to experimental data. See: http://www.cathod...nism.pdf

How can I compare my model to what you call is "your model", when "your model" has not been quantified and fitted to any experimental data? Nor do your utterings on this forum make even qualitative sense. The fact is that you do not have a model to which any real models can be compared to.

If you keep on being unable to understand the latter fact, as you have proved time and again on this forum is the case, you should refrain from commenting on physics. You just do not have the understanding of what physics really entails.
Osteta
Jan 29, 2014
This comment has been removed by a moderator.
johanfprins
not rated yet Jan 29, 2014
How can I compare my model to what you call is "your model", when "your model" has not been quantified and fitted to any experimental data
You doubted my proposal, that the dopant atom "suck" an electrons from outside? If you cannot judge it without math - as you're pretending right now - why you cannot simply remain quiet about it?


Why should I keep quiet about it when I know it is wrong? You have no experimental proof that this is occurring except your hallucinating intuition. If you claim this is happening it is incumbent on YOU to propose an experiment which can prove that this is actually happening.

Or do the next best thing: You must use your "sucking" hypothesis to obtain a quantitative fit to valid experimental results. These are the rules of physics: If you cannot follow these rules you should get out of the kitchen, since you are then not contributing a darn thing to physics:

I just cannot believe that you can think that you can contribute to physics.
Nestle
not rated yet Jan 29, 2014
Why should I keep quiet about it when I know it is wrong?
Why it is wrong? The positively charged atoms within atom lattice attract the electrons in the same way, like the positively charged oxygen ions attract the electrons to the surface of diamond. It's the same stuff. Why do you think the electrons are supposed to create the superconductive phase at the diamond surface? They're attracted to it.
you must use your "sucking" hypothesis to obtain a quantitative fit to valid experimental results
You have only to die. I have to do anything else. The physics as you know it will not interest anyone soon.
johanfprins
not rated yet Jan 30, 2014
Why it is wrong? The positively charged atoms within atom lattice attract the electrons in the same way, like the positively charged oxygen ions attract the electrons to the surface of diamond.


Any person who claims that Solid State Physics at a surface is identical to what is happening in the bulk, does not know his physics,

Why do you think the electrons are supposed to create the superconductive phase at the diamond surface?


I have modelled this quantitatively and the model has been in the public domain since 2005. So if you want to know what I think, you should simply read what I have published.

You have only to die. The physics as you know it will not interest anyone soon.


Obviously, all physics might change in future. But if my model has to change, it has to be proved quantitatively that it is wrong. This has not happened since 2005. Your "sucking" hypothesis has also not done this to date.

Stop "sucking" hallucinations from your thumb!