Scientists developed a high-performance superconducting material by mixing iron and selenium

Oct 29, 2012

(Phys.org)—Physicists describe how they have synthesized a new material that belongs to the iron-selenide class of superconductors, called LixFe2Se2(NH3)y, in a paper about to be published in EPJ B. The work was carried out by Ernst-Wilhelm Scheidt from the University of Augsburg and colleagues. This material displays promising superconducting transition temperatures of 44 Kelvins (K) at ambient pressure, thus improving upon traditional copper-based high-temperature superconductors.

The ultimate goal of scientists developing such materials is to reach superconducting characteristics at temperatures above that of (77K), which is the benchmark temperature to make them attractive for applications.

Until now, superconductors based on iron and arsenic discovered in 2008 worked at 56K. As recently as 2010 attempts to develop other materials replacing arsenic with selenium yielded iron-selenium materials with an intercalation of potassium, rubidium, cesium or thalium. These materials, belonging to the family of iron chalcogenide materials, reached a superconducting temperature of 32 K.

The authors have now used a method to intercalate lithium atoms between layers of iron and selenium. Similar to the way a cocktail would generate an exciting new flavour, stirring all these ingredients for several hours in liquid ammonia produced exciting new . They found that these properties are controlled by electronic doping and expansion of the iron-selenium material's , which is gained by intercalating the lithium-based electronic donor molecules.

Unlike previous attempts, the authors showed in this study that these materials can be successfully synthesised with a remarkable degree of purity. In addition, the fraction of the material that is superconductive was almost 80 percent, the highest reported for materials in the intercalated iron chalcogenides family.

Going one step further, the authors also showed that using sodium instead of lithium will further increase the superconducting temperature to 45.5 K.

Explore further: Looking for novel forms of superconductivity: Two-dimensional electron liquids

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User comments : 7

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johanfprins
1 / 5 (3) Oct 30, 2012
So what!?
ValeriaT
1 / 5 (2) Nov 01, 2012
Why the experiments of J.F.Prins and Joe Eck aren't attempted to replicate in peer-reviewed press while this useless research continues to consume the money of tax payers?
johanfprins
1 / 5 (5) Nov 01, 2012
Why the experiments of http://www.newsci...rch.html aren't attempted to replicate in peer-reviewed press while this useless research continues to consume the money of tax payers?


Thank you ValeriaT: Although we do not agree on theory, we agree fully on how scientific research should be done. The latter is more important than theory since it can override wrong theory: And the latter is what physics should all be about.

A Fermi stated: When you measurements are in line with theory you have made a confirmation, when they contradict theory, you have made a discovery.

Modern physicists do everything in their power to prevent new discoveries which contradict accepted theories. It is criminal!
VendicarD
5 / 5 (1) Nov 01, 2012
Isn't it interesting that ValeriaT is no longer hyping Cold Fusion now that E-Cat has been shown to be a fraud?

But his underlying anti-science philosophy remains despite it's failure.
johanfprins
1 / 5 (5) Nov 01, 2012
Isn't it interesting that ValeriaT is no longer hyping Cold Fusion now that E-Cat has been shown to be a fraud?

But his underlying anti-science philosophy remains despite it's failure.

How long is it going to take to prove that the recent discovery at CERN is fraud? There is no experiment possible to give a falsifiable proof that this blip on the screen causes matter to have rest-mass energy!

Did ValeriaT "hype" cold fusion, or did he only keep an open mind? Can you give irrevocable proof that cold fusion will never be possible? Note I am NOT stating that it IS possible, but I am also not such a bigot to say it IS NOT possible.

Since you can cold-fuse two electrons to form a covalent bond why not two deuterium-nuclei to form a helium nucleus?
lengould100
5 / 5 (3) Nov 04, 2012
joh: Comparing an electromagnetic bond (electrons covalent) with a weak-force bond (protons and neutrons in an atomic nucleus), trying to get gullible people to think they are the same, is preposterous.
johanfprins
1 / 5 (3) Nov 04, 2012
Comparing an EM bond (electrons covalent) with a weak-force bond (protons and neutrons in an atomic nucleus), trying to get gullible people to think they are the same, is preposterous.


The helium nucleus (alpha-particle) is a VERY stable entity which can be formed by forcing two deuteron-waves until they overlap completely. An enormous amount of energy is released when you succeed: Thus it cannot be a "weak force" in this case.

this "particle" is a single holistic-wave: therefore it is a stable entity which is ejected during radioactive decay.

Similarly when two electrons form a covalent bond, their waves overlap and energy is released. The bond is then also a single holistic-wave, not two separate electrons being held together by an exchange of "virtual" photons.

But, IN ADDITION, separate holistic waves can borrow, or lend out, energy (D)E for a time (Dt) (Heisenberg's "uncertainty"). This explains effects like the Casimir-force, superconduction, the Lamb-shift etc.