A group of Russian scientists under the direction of Professor Artem Oganova from the Skolkovsky Institute of Science and Technologies found unique high-temperature superconductors, whose critical temperature of superconductivity reaches minus 20 degrees Celsius (253 Kelvin). An article with the results of the study was published in the Materials Today magazine. You can get acquainted with the scientific work in more detail on preprint on the site ARXIV.
Experts studied the properties of unusual substances called superhydrides, which have an unusually high number of hydrogen atoms. Among them are well known for sulfur super hyphenride (H3S), which has high-temperature superconductivity from minus 82 to minus 69 degrees Celsius (191-204 Kelvin). In fact, this compound is a doped metal hydrogen, which becomes superconductable at a pressure of 1.5 million atmospheres (metallic hydrogen in natural form is in the depths of gas giants – approx. Tape.ru). It broke a long time holding a record of copper compounds (Cuprats), in which superconductivity occurs at 92 Kelvin.
Recently, even higher temperature conductors based on Lanthan hydrides (Lah10) and Yttria (YH6 and YH9) were successfully synthesized. But since the possibilities of the latter (called double hydrides) were exhausted, scientists moved to the study of triple hydrides, in which hydrogen is associated with a metal alloy, for example, from Yttria and Lantane (LA-Y).
In the new scientific work of the chemists experimentally studied the properties of superconductivity in hexagidride with the general formula La (x) y (1-x) H6 and decahydride (La (x) y (1-x) H10). Previous theoretical studies have shown that such hydrides called triple, the critical temperature of superconductivity increases compared to binary hydrides. It is predicted that the La-Y-H suprameability temperature can reach 274 Kelvin (almost one degree Celsius) at a pressure of 190 gigapascal (1.8 million atmospheres).
samples were compressed in cells with diamond anvils to reach a pressure of 165-196 gigapascals and heated a series of laser pulses with a duration of millisecond. It turned out that the critical temperature of superconductivity in hexagidride reaches 237 ± 5 Kelvinov, and the decahydride is approximately 253 Kelvin. Thus, Russian scientists managed to obtain unique high-temperature superconductors based on triple hydrides. They are still inferior to binary hydrides, for example, LAH10 (record 260 K at 170 gigapascals), however, by the density of the superconducting current decahydride, we compare with industrial superconductors of the NBTI type or NB3SN type.
The results of the study demonstrated that although super-hydrides with a large number of hydrogen become unstable in pure form, which limits the use of binary hydrides, they can be stabilized in the form of triple hydrides, which opens the way to create superconductors at record high temperatures of superconductivity and at a lower pressure. .