Researchers discovered trace amounts of superconductive grains in this piece of Mundrabilla meteorite, which is the first identification of superconductive grains in a meteorite. (Image Credit: James Wampler)
Scientists from UC San Diego and Brookhaven Laboratory in New York have discovered trace amounts of superconductive material inside two meteorites. After examining 15 pieces of comets and asteroids, they found that two meteorites named “Mundrabilla” and “GRA 95205” contain superconductive grains. The researchers published their findings in the Proceedings of the National Academy of Sciences.
Meteorites present researchers with a wide range of material phases from the oldest state of the solar system. However, they’re also difficult to detect due to the minute measurability of the phases. The team was able to overcome that obstacle by using an ultrasensitive measurement technique known as magnetic field modulated microwave spectroscopy (MFMMS).
The team characterized the different phases of the meteorite as alloys of lead, tin and indium. Their findings could have an impact in the astronomical field by understanding how superconductivity particles in cold environments could affect planet formation, shape and magnetic fields’ origin, dynamo effects, the motion of charged particles and much more.
“Naturally occurring superconductive materials are unusual, but they are particularly significant because these materials could be superconducting in extraterrestrial environments,” said James Wampler, a postdoctoral researcher in the Schuller Nanoscience Group.
After the team resolved the detection challenges by using MFMMS, they measured individual samples, which allowed them to set apart the grains that contained the largest superconductivity fraction. Then, by using vibrating sample magnetometry (VSM), energy-dispersive X-ray spectroscopy (EDX) and numerical methods, the researchers were able to characterize each of the grains. “These measurements and analysis identified the likely phases as alloys of lead, indium and tin,” said Wampler.
According to Mark Thiemens, a chemistry and biochemistry professor, meteorites that have been formed in extreme conditions are excellent for studying exotic chemical species, like superconductors. “My part of the project was to determine which of the tens of thousands of meteorites of many classes was a good candidate and to discuss the relevance for planetary processes; one from the iron-nickel core of a planet, the other from the more surficial part that has been heavily bombarded and was among the first meteorites where diamonds were observed,” said Mark Thiemens, a chemistry and biochemistry professor.
Both meteorites have some unique properties. Mundrabilla is rich in iron-sulfide, and the meteorite was formed after melting and cooling over a long period of time. Meanwhile, GRA 95205 is made of ureilite, which is an extremely rare stony-like piece with special mineral properties that survived heavy shocks during formation. “Naturally collected materials are not phase-pure materials. Even the simplest superconducting mineral, lead, is only rarely found in its native form,” Schuller said.
The researchers only knew about natural superconductivity in covellite. Since the superconductivity phases actually exist in two different meteorites, it’s very likely it can also be found in other meteorites.
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