Superconductors found in two meteorites

American scientists have discovered extraterrestrial superconducting materials in two samples, which belong to the meteorites Mundrabilla (Mandrabilla) and GRA 95205. To do this, they analyzed 15 samples of cosmic bodies that have fallen to the ground at different times. Work published in the journal Proceedings of the National Academy of Sciences.

Superconductivity cannot be explained using classical physics: is a quantum phenomenon which allows some materials to conduct electrical current with absolutely no resistance. Today, scientists know a few of the hundreds of pure materials, alloys, ceramics and compounds which are able to go superconducting at different temperatures. Until the 1980s, years physicists have been known materials with relatively low transition temperature to the superconducting state (of the order of several Kelvin). However, it soon turned out that there are materials with much higher transition temperature — high-temperature superconductors: they can be used in the superconducting state at the boiling point of liquid nitrogen is about 77 Kelvin.

No less important characteristic of the superconducting state is the Meissner effect — the complete expulsion of magnetic field from the volume of the superconductor. This effect can be observed with levitation of a magnet above a cooled to the critical temperature of the superconductor. Because a superconductor will not allow magnetic field inside, it creates currents on its surface, a magnetic field which counteracts the external field. So the magnet is repelled from the surface of the superconductor and is forced to float in the air for as long as the superconductor would be heated to the critical temperature.

A group of physicists led by James Wampler (James Wampler) from the University of California in San Diego started with the search for superconductors of extraterrestrial origin. To do this, they examined samples of 15 different meteorites by the method of ultrasensitive microwave spectroscopy with magnetic field modulation. Scientists irradiated the samples by microwave radiation and gradually cooled them, watching the response of their magnetic fields. When the critical temperature on the chart forms a peak, which can be used to register the phase transition. This method is several orders of magnitude more sensitive than standard methods of working with superconductors: only enough to register the small quantity of the superconducting substance found in meteorites. The result was that two of the meteorite from 15 Mundrabilla and GRA 95205 — contain superconducting materials. Their critical temperature is about 5 Kelvin.

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