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Since their first discovery in 1911 , superconductors — materials which perfectly impart electricity — have long beguiled and tantalized physicists .
Superconductors are used in corpuscle accelerators , nuclear fusiondevices , MRI automobile , and even maglev caravan . Yet blanket and more common applications are hampered by a ominous temperature limit — so far , no superconductor has been raise to work at ambient force per unit area and temperatures .
An artist’s concept image of a levitating superconductor.
On July 22 , scientists in South Koreapublished research claiming to have solve this job . They say that their material , call in LK-99 , has an electric resistivity , or resistance to the flow of electrical current , that drops to near zero at 30 degrees Celsius ( 86 degrees Fahrenheit ) . Their claims have sparked a orbicular race to play the cloth and test its properties . As of August 4 , no one has yet been capable to replicate the results .
Here ’s everything you want to jazz about superconductors .
What is superconductivity?
All fabric own a prop known as resistance — examine to send an electric flow through them , and some of the vim in the electric current inevitably gets lost . This is because the current - carry electrons collide with ions joggle inside the material , create opposition to their menstruum .
But cool down a material down so that the ions inside it have less energy to vibrate , and the collision rate shake off , sharply lowering the resistivity . Most materials would need to get to the insufferable - to - strive state of right-down zero to have zero resistivity , yet some rare materials can attain zero impedance above absolute zero temperatures — we call these materials superconductors .
The first superconductor was discovered in 1911 after the Dutch physicist Heike Kamerlingh Onnes noticed that a supercooled mercury conducting wire ( its temperature lowered to roughly minus 452 F ( minus 269 C ) no longer resisted the menses of electrical energy ; an observation which won him theNobel Prize in Physics . His observations were before long made using other element such as lead , niobium , and tin .
Currently, extreme cold is required to achieve superconductivity, as shown in this photo of a magnet floating above a superconductor cooled with liquid nitrogen.
How do superconductors work?
Despite Onnes ’s find , explaining why it happened would take decennium .
The account finally emerged in 1957 under the name of theNobel Prizewinning “ BCS theory ” . Named after its discoverers John Bardeen , Leon Cooper and John Robert Schrieffer , BCS theory excuse that superconductivity emerge from ripples because of negatron as they moved through the textile . At low enough temperatures , these ripples cause atomic nuclei insideatomsto become drawn to each other , in turn causing a slight offset in tutelage that attract a 2d electron to the first . The military group of this attraction induce something strange to bump : Instead of repelling each other through the force of static horror , the electrons instead get bound together into a “ Cooper pair . ”
barrel maker pairs observe differentquantum mechanicalrules from those of solitary negatron . Instead of stacking on top of each to make energy case , they play like particles of light — an countless number of which can occupy the same point in space at the same clock time . Create enough of these Cooper copulate throughout a stuff , and they become a superfluid , fall without any departure of energy . Stir a superfluid once , and it will theoretically remain swirling until the end of the universe .
But this was far from the final surprise superconductivity had in store for physicists . In 1986 , the previous Alex Müller and Georg Bednorz , both of IBM , institute that materials called cuprates — made up of layers of fuzz and oxygen sandwich between other elements — could superconduct at temperatures as mellow as minus 211 F ( minus 135 ascorbic acid ) .
Exactly why this go on is still not totally understood , but the prevalent possibility is oneproposed by the American physicist Phillip Anderson , who intimate that electrons will take to switch office with each other through a quantum mechanical physical process shout superexchange .
Electrons incessantly seek to switch places because , much like all particle and many thing in nature , they seek to occupy the depressed possible energy country . As Heisenberg ’s doubt principle states that only a particle ’s position or momentum can be distinctly known at one clip , the electrons move to make their billet the most unsure and their impulse the most clearly defined .
This constant switching , in turn , mean that the electrons ’ energies can be more sharply defined , enabling them to sink down into the low-pitched possible Department of Energy nation . And the ideal configuration for this shift to take place ? It just so happens to be a sea of evenly - spaced Cooper duo .
Somerecentexperimentshave suggested that Anderson was right — at least in the materials they hit the books — yet superexchange could theoretically be just one type of electron glue among many . Just as unsure is how high a temperature some of these hypothetical negatron glues could operate at , and what manufacture materials could produce these electron gum .
Superconductors have one telltale property : levitation . Because a flowing current generates amagnetic battleground , as materials transition to superconductive states the negatron inside menstruation without friction , render amagnetic fieldthat can repulse an external magnet with an equal and opposite force . Place a superconductor above a magnet and it will be perfectly suspended in the air , a phenomenon foretell the Meissner consequence .
Are room temperature superconductors possible?
elbow room temperature superconductors do n’t violate any known physics theories , but neither do any hypothesis predict them .
The difficulty of create them boils down to an engineering science puzzler , with a minacious raiment of atoms and chemical substance prop across many combination of materials to test .
Among the materials scientist have tested isgraphene , which can have its low - temperature superconductivity switched on or off depending on the twist and turns of its one - atom - thick shroud . Another hopeful campaigner is the element atomic number 21 , a silvery metallic element which , this class , researchers reportedcan superconduct at ardent ( but still very insensate ) temperature .
Onto this crowded picture comes LK-99 , a cloth whose impedance , its researcher claim , omit to near zero at 86 F ( 30C ) . The material is made up of mixed powders containing lead , O , S and phosphorus which is dope with cop . It is also relatively sluttish to manufacture and mental test .
So far , 11 attack to replicate the results have been announce by scientific mental institution and seven have declared results . Of these seven , three have found properties similar to those claimed for LK-99 , but not superconductivity . The remain four note neither magnetism nor superconductivity .
