Room-temperature superconductors could zap us into the future

Date:
Sat, 25 Mar 2023 16:00:00 +0000

Description:
In this image, the superconducting Cooper-pair cuprate is superimposed on a dashed pattern that indicates the static positions of electrons caught in a quantum "traffic jam" at higher energy. US Department of Energy Superconductors convey powerful currents and intense magnetic fields. But right now, they can only be built at searing temperatures and crushing pressures. The post Room-temperature superconductors could zap us into the future appeared first on Popular Science .

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In this image, the superconducting Cooper-pair cuprate is superimposed on a dashed pattern that indicates the static positions of electrons caught in a quantum "traffic jam" at higher energy. US Department of Energy

In the future, wires might cross underneath oceans to effortlessly deliver electricity from one continent to another. Those cables would carry currents from giant wind turbines or power the magnets of levitating high-speed
trains.

All these technologies rely on a long-sought wonder of the physics world: superconductivity, a heightened physical property that lets metal carry an electric current without losing any juice.

But superconductivity has only functioned at freezing temperatures that are far too cold for most devices. To make it more useful, scientists have to recreate the same conditions at regular temperatures. And even though physicists have known about superconductivity since 1911, a room-temperature superconductor still evades them, like a mirage in the desert . What is a superconductor?

All metals have a point called the critical temperature. Cool the metal below that temperature, and electrical resistivity all but vanishes, making it
extra easy to move charged atoms through. To put it another way, an electric current running through a closed loop of superconducting wire could circulate forever.

Today, anywhere from 8 to 15 percent of mains electricity is lost between the generator and the consumer because the electrical resistivity in standard wires naturally wicks some of it away as heat. Superconducting wires could eliminate all of that waste.

[Related: This one-way superconductor could be a step toward eternal electricity ]

Theres another upside, too. When electricity flows through a coiled wire, it produces a magnetic field; superconducting wires intensify that magnetism. Already, superconducting magnets power MRI machines , help particle accelerators guide their quarry around a loop, shape plasma in fusion
reactors , and push maglev trains like Japans under-construction Ch Shinkansen. Turning up the temperature

While superconductivity is a wondrous ability, physics nerfs it with the cold caveat. Most known materials critical temperatures are barely above absolute zero (-459 degrees Fahrenheit). Aluminum, for instance, comes in at -457 degrees Fahrenheit; mercury at -452 degrees Fahrenheit; and the ductile metal niobium at a balmy -443 degrees Fahrenheit. Chilling anything to temperatures that frigid is tedious and impractical.

Scientists made it happenin a limited capacityby testing it with exotic materials like cuprates, a type of ceramic that contains copper and oxygen.
In 1986, two IBM researchers found a cuprate that superconducted at -396 degrees Fahrenheit, a breakthrough that won them the Nobel Prize in Physics . Soon enough, others in the field pushed cuprate superconductors past -321 degrees Fahrenheit, the boiling point of liquid nitrogena far more accessible coolant than the liquid hydrogen or helium theyd otherwise need.

That was a very exciting time, says Richard Greene , a physicist at the University of Maryland. People were thinking, Well, we might be able to get
up to room temperature.

Now, more than 30 years later, the search for a room-temperature superconductor continues. Equipped with algorithms that can predict what a materials properties will look like, many researchers feel that theyre closer than ever. But some of their ideas have been controversial. The replication dilemma

One way the field is making strides is by turning the attention away from cuprates to hydrates, or materials with negatively charged hydrogen atoms. In 2015, researchers in Mainz, Germany, set a new record with a sulfur hydride that superconducted at -94 degrees Fahrenheit. Some of them then quickly
broke their own record with a hydride of the rare-earth element lanthanum , pushing the mercury up to around -9 degrees Fahrenheitabout the temperature
of a home freezer.

But again, theres a catch. Critical temperatures shift when the surrounding pressure changes, and hydride superconductors, it seems, require rather inhuman pressures. The lanthanum hydride only achieved superconductivity at pressures above 150 gigapascalsroughly equivalent to conditions in the Earths core, and far too high for any practical purpose in the surface world.

[Related: How the small, mighty transistor changed the world ]

So imagine the surprise when mechanical engineers at the University of Rochester in upstate New York presented a hydride made from another
rare-earth element, lutetium . According to their results , the lutetium hydride superconducts at around 70 degrees Fahrenheit and 1 gigapascal. Thats still 10,000 times Earths air pressure at sea level, but low enough to be
used for industrial tools.

It is not a high pressure, says Eva Zurek , a theoretical chemist at the University at Buffalo. If it can be replicated, [this method] could be very significant.

Scientists arent cheering just yet, howevertheyve seen this kind of an
attempt before. In 2020, the same research group claimed theyd found room-temperature superconductivity in a hydride of carbon and sulfur . After the initial fanfare, many of their peers pointed out that theyd mishandled their data and that their work couldnt be replicated. Eventually, the University of Rochester engineers caved and retracted their paper .

Now, theyre facing the same questions with their lutetium superconductor. Its really got to be verified, says Greene. The early signs are inauspicious: A team from Nanjing University in China recently tried to replicate the experiment , without success.

Many groups should be able to reproduce this work, Greene adds. I think well know very quickly whether this is correct or not.

But if the new hydride does mark the first room-temperature
superconductorwhat next? Will engineers start stringing power lines across
the planet tomorrow? Not quite. First, they have to understand how this new material behaves under different temperatures and other conditions, and what it looks like at smaller scales.

We dont know what the structure is yet. In my opinion, its going to be quite different from a high-pressure hydride, says Zurek.

If the superconductor is viable, engineers will have to learn how to make it for everyday uses. But if they succeed, the result could be a gift for world-changing technologies.

The post Room-temperature superconductors could zap us into the future appeared first on Popular Science . Articles may contain affiliate links
which enable us to share in the revenue of any purchases made.



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Link to news story: https://www.popsci.com/science/room-temperature-superconductor/


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