The dream of superconductors – materials that transmit electricity with no resistance – at room temperature is inching closer toward reality. Traditionally, superconductors need to be cooled to almost absolute zero (–273.15°C, −459.67°F) for their zero-resistance effects to be felt. However, scientists are slowly pushing this limit to higher temperatures, and this newest method works at the highest temperature yet: –70°C (–94°F). This is still extremely chilly for humans, but for superconductors the temperature is positively balmy.
This superconducting material, developed by researchers from the Max Planck Institute for Chemistry in Mainz, Germany, is made out of something that might leave a bad taste in your mouth: hydrogen sulfide, commonly associated with the smell of rotten eggs. It was crushed in a diamond anvil with up to 1.6 million times atmospheric pressure to turn it into a superconducting material.
And the research might mean the start of "spring" for the progress of superconductors. In fact, the temperature at which the material displays superconductive properties is nearly twenty degrees warmer than the lowest recorded natural temperature on Earth: –89.2°C (–129°F) in Antarctica. The nearest high temperature for a functioning superconductor was –110°C (–166°F), but the new material smashes this record. You can see these "cool" results published in Nature.
A superconductor is a material that loses all of its electrical resistance when it is cooled down. This is because the natural kinetic motion of warm atoms in the superconductor disrupts the flow of electrons and, therefore, the electricity flow. However, when these atoms are cold, they stop vibrating around quite as vigorously, and electrons are free to zoom along the material. Superconductivity is a desirable property because it reduces input energy for electricity being wasted as heat. The new material isn't a superconductor in its own right, but has the properties of one.
Now that scientists are starting to produce these low-resistance conditions at warmer and warmer temperatures, the technology becomes more accessible to wider and more commercial fields. A common example is in computing. Computer components with low electrical resistance would make computers faster and, therefore, more powerful. It's completely unrealistic to consider using computers cooled down to near absolute zero, but –70°C starts to become feasible. We might need to wait for an even warmer superconductor before we start seeing them in our laptops though.
Christoph Heil, from the Graz University of Technology in Austria, who was not part of the study, believes that it is the immense pressure that "locks" the otherwise jiggling atoms into place. This may be the reason that the compound has similar properties to a low-temperature superconductor at higher temperatures.
Another theory explaining the low resistance in the material involves something called "Cooper pairs", which are created when a superconductor cools down. This is where the material pairs up its electrons in a sort of long-distance bond. The result is that the electrons flow without resistance through the material. The hydrogen atoms in this compound material provide the perfect platform to form strong Cooper pairs at temperatures greater than ever before.
Admittedly, further research will be needed to confirm the findings. But in the meantime, this result has rustled up a lot of interest in the scientific community. The next step will be to repeat the results, and maybe to explore other avenues for warm, superconducting compounds, such as hydrogen mixed with platinum, potassium or selenium.
Superconductors are well-known for exhibiting a fun and fascinating property called the Meissner effect, as seen above. This happens when a superconductor is placed in an external magnetic field. Eerily, there is no magnetic field inside the superconductor and strange things start to happen: the material floats.