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Using solid state nuclear magnetic resonance (SSNMR) techniques, scientists from the Ames laboratory of the US Department of Energy discovered a new quantum criticality in a superconducting material , to better understand the link between magnetism and unconventional superconductivity.
Most iron-arsenide superconductors exhibit magnetic and structural (or nematic) transitions, making it difficult to understand the role they play in superconducting states. But a compound of calcium, potbadium, iron and arsenic, doped with small amounts of nickel, CaK (Fe1-xNix) 4As4, first manufactured in the laboratory of Ames, was discovered to have a new magnetic state called a hedgehog vortex. Crystalline antiferromagnetic state without nematic transition.
"Spinal or nematic fluctuations can be considered to play an important role in unconventional superconductivity," said Yuji Furukawa, senior scientist at Ames Laboratory and professor of physics and astronomy at Iowa State University. "With this particular material, we could only examine magnetic fluctuations, and NMR is one of the most sensitive techniques for examining them." He continued "Using the 75As NMR, we found that CaKFe4As4 is located at a critical antiferromagnetic quantum point of spin-vortex hedgehog crystal avoided because of superconductivity, that spin fluctuations are the main factor of superconductivity. "
Furukawa's discovery is a collaboration between the Ames Laboratory Laboratory's SSNMR's leading-edge team and the laboratory's condensed matter physicists, including Paul Canfield, Senior Research Scientist at Ames Laboratory and Professor. distinguished. Professor of Physics and Astronomy Robert Allen Wright of Iowa State University
"This is a new kind of magnetic order," said Mr. Canfield. "You have this interesting interaction between superconductivity and magnetism from high temperatures in the normal state, which gives us an idea of the fact that this high-temperature superconductivity could come from this almost quantum critical antiferromagnetic transition."
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Materials Provided by DOE / Ames Laboratory . Note: Content can be changed for style and length.
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