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lunedì 29 gennaio 2018

# chem: extreme superconductive in random atomic-scale mixture

<< High-entropy alloys (HEAs) are a new class of materials that are composed of multiple transition-metal elements in equimolar or near-equimolar ratios >>

<< many HEAs have been found in disordered solid-solution phases with body-centered-cubic, hexagonal closest-packed, and face-centered-cubic crystal structures >>

<< In many respects, HEAs display novel properties, including ultrahigh fracture toughness at cryogenic temperatures, excellent specific strength, and superior mechanical performance at high temperatures. In addition to their promising mechanical properties, some HEAs also exhibit interesting electronic properties: [TaNb]1−x(ZrHfTi)x HEAs were found to display superconductivity, for example >>

AA << report high-pressure studies on the superconducting HEA (TaNb)0.67(HfZrTi)0.33, [..] this alloy exhibits extraordinarily robust superconductivity - its zero-resistance superconducting state is still achieved even at a pressure of 190.6 GPa, or almost 2 megabars (1 Mbar = 1011 pascal), a pressure like that within the outer core of the earth. >>

Jing Guo, Honghong Wang, et al.  Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa. PNAS 2017; 114 (50) 13144-7.  doi: 10.1073/pnas.1716981114.

http://www.pnas.org/content/114/50/13144

Laura Mgrdichian. A material that superconducts continuously up to extreme pressures.  Jan 17, 2018

https://m.phys.org/news/2018-01-material-superconducts-extreme-pressures.html

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