THIRD NATURAL SOURCE OF QUASICRYSTALS

  • Scientists have reported finding only the third natural source of quasicrystals, a material once deemed impossible and whose unusual properties scientists are still unravelling.
  • In a crystal, the atoms are arranged in a pattern that periodically repeats itself. A quasicrystal’s atoms are arranged in a pattern that repeats itself at irregular intervals.
  • Quasicrystals were discovered in the lab in 1982. In the late 1990s, scientists began looking for quasicrystals in nature.
  • After a decade-long quest, Luca Bindi, Paul Steinhardt, and others reported finding the first natural quasicrystal in 2009 – as microscopic grains in a piece of the Khatyrka meteorite in the Koryak mountains of Russia.
  • This meteorite was involved in several collisions in space over millions of years, heating and pressurising it to a great degree and creating the quasicrystals.
  • The discovery inspired a series of experiments in which physicists used ‘shock synthesis’ to create new varieties of quasicrystals in the lab.
  • In 2021, Dr. Bindi, Dr. Steinhardt, and others reported finding a quasicrystal in the remains of the first nuclear weapon test, conducted on July 16, 1945, in New Mexico.
  • They wrote that the material “was found in a sample of red trinitite, a combination of glass fused from natural sand and anthropogenic copper from transmission lines used during the test.”
  • Recently, in a study published in PNAS in December 2022, Dr. Bindi, Dr. Steinhardt, and others reported that in the wind-blown dunes of northern Nebraska, they had uncovered a metallic fragment in a long, tube-shaped mass of sand heated and fused by a heavy electric current.
  • They also noticed a power line nearby had fallen to the ground. That’s where the metal could have come from, but they couldn’t tell where the current had originated: in the power line or as a lightning strike on a stormy night.
  • Whatever the source, it had melted the quartz at the site and formed a silicate glass – a process that needs to happen at at least 1,700º C. The metallic portion was a mass of aluminium, chromium, manganese, nickel, and silicon.
  • When Bindi et al. placed it under a powerful electron microscope, they spotted a dodecagonal quasicrystal, rare even for quasicrystals.

SOURCE: THE HINDU, THE ECONOMIC TIMES, PIB

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