University of Chicago scientists are part of an international research team that has discovered superconductivity – the ability to conduct electricity perfectly – at the highest temperatures ever measured. The team studied a class of materials in superconductivity at temperatures of about minus 23 degrees Celsius (minus 9 degrees Fahrenheit) was observed – a jump of about 50 degrees compared to the previously confirmed record.
However, superconductivity has ceased At extremely high pressure, the result is still a big step towards superconductivity at room temperature – the ultimate goal for scientists to use this phenomenon for advanced technologies. The results were published on May 23 in the journal Nature . Vitali Prakapenka, a research professor at the University of Chicago, and Eran Greenberg, a postdoctoral fellow at the University of Chicago, are co-authors of the research.
Just as a copper wire safely conducts electricity better than a rubber hose Types of materials can become better superconducting, a condition defined by two main characteristics: The material does not resist electrical current and can not be penetrated by magnetic fields. The potential applications for this are as great as they are exciting: electroless electrical cables, extremely fast supercomputers and efficient magnetic levitation railways.
Until now, however, scientists have only been able to produce superconducting materials when cooled to extremely cold temperatures ̵
Recent theoretical predictions have shown that a new class of superconducting hydrides could pave the way for superconductivity at higher temperatures. Researchers at the Max Planck Institute for Chemistry in Germany, in collaboration with researchers from the University of Chicago, have produced one of these materials, lanthanum superhydride, which tests its superconductivity and determines its structure and composition.
The only catch was that the material needed was put under extremely high pressure – between 150 and 170 gigapascals, more than one and a half million times the pressure at sea level. Only under these high pressure conditions did the material – a tiny sample of only a few micrometers in diameter – show superconductivity at the new record temperature.
In fact, the material had three of the four properties required to detect superconductivity: it lowered its electrical resistance, lowered its critical temperature under an external magnetic field, and exhibited a temperature change when some elements were replaced by other isotopes. The fourth feature, the Meissner effect, where the material ejects a magnetic field, has not been detected. According to researchers, the material is so small that this effect could not be observed.
They used the Advanced Photon Source of the Argonne National Laboratory, which provides ultra-bright, high-energy X-rays that enabled breakthrough everything from better batteries to understanding the deep Earth's interior to analyze the material. In the experiment, researchers from the University of Chicago's Center for Advanced Radiation Sources pressed a tiny sample of material between two tiny diamonds to apply the required pressure, and then used the X-rays of the beamline to study its structure and composition.
The temperatures used to conduct the experiment are normal in many places around the world, so the ultimate goal of room temperature – or at least 0 degrees Celsius – seems to be within reach.
The team is already working together to find new materials that can produce superconductivity under more reasonable conditions.
"Our next goal is to reduce the pressure required for sample synthesis, bring the critical temperature closer to ambient temperature and possibly even produce samples that could be synthesized at high temperatures pressures, but still superconductivity at normal Press, "said Prakapenka. "We continue to search for new and interesting connections that bring us new and often unexpected discoveries."