The High-temperature Superconductor Was Stabilized At Low Pressure
Physicists have created a new high-temperature superconductor based on a compound of selenium and iron. It retains its properties even after the pressure inside drops to very low values. The results of the study are available in the scientific journal Proceedings of the National Academy of Sciences.
"Thanks to our method, it is possible to create materials that will maintain a high superconductivity temperature at atmospheric pressure. There is no reason to believe that this technique cannot be used to create superconductors based on metal hydrides, which have recently come close to "room" superconductivity," said one of the authors of the study, a professor at the University of Houston (USA) Paul Chu.
In recent years, scientists have created several new types of superconductors that operate at very high temperatures for such materials. For example, even ordinary hydrogen sulfide can be such a superconductor if it is compressed to several million atmospheres.
One of the most crucial problems that scientists face when working with such substances is how to stabilize such superconductors at a lower pressure. Thus, it would be possible to work with them not only in special laboratory conditions but also in industry and everyday life. Chu and his colleagues figured out how to deal with it.
According to the physicist, this idea is essentially very similar to the method of obtaining the first artificial diamonds, which were developed in 1955 by the American inventor Francis Bundy. According to this method, precious stones can be obtained if graphite or other carbon materials are strongly compressed, and then the pressure is sharply reduced to almost zero.
American physicists have tested whether it is possible to improve the properties of superconductors in a similar way. To do this, they prepared a superconductor based on a compound of selenium and iron, which loses its properties if its temperature is above 9 kelvin (-264 °C). If such a material is compressed to 25-30 thousand atmospheres, then this indicator grows to 35-37 kelvins.
The experiments of Chu and his colleagues showed that a rapid decrease in pressure stabilizes the material and allows it to maintain a high transition temperature to a superconducting state even at normal atmospheric pressure for at least a week.
When scientists heated the material to 300 kelvins, this indicator decreased only partially – it fell to 20, not 9 kelvins. Scientists suggest that this is since a sharp decrease in pressure during compression of a mixture of selenium and iron irreversibly changed the structure of this substance.
Physicists assume that their technique will similarly affect the properties of other materials, including compounds of hydrogen, metals, and sulfur. They hope that such superconductors can be created in the course of further experiments.