Using solid state nuclear magnetic resonance (ssNMR) techniques, scientists at the U.S. Department of Energy's Ames Laboratory discovered a new quantum criticality in a superconducting material, leading to a greater understanding of the link between magnetism and unconventional superconductivity.

Most iron-arsenide superconductors display both magnetic and structural (or nematic) transitions, making it difficult to understand the role they play in superconducting states. But a compound of calcium, potassium, iron, and arsenic, and doped with small amounts of nickel, CaK(Fe1-xNix)4As4, first made at Ames Laboratory, has been discovered to exhibit a new magnetic state called a hedgehog spin-vortex crystal antiferromagnetic state without nematic transitions.

"Spin or nematic fluctuations can be considered to play an important role for unconventional superconductivity," said Yuji Furukawa, a senior scientist at Ames Laboratory and a professor of Physics and Astronomy at Iowa State University. "With this particular material, we were able to examine only the magnetic fluctuations, and NMR is one of the most sensitive techniques for examining them."

He continued, "using 75As NMR, we discovered that CaKFe4As4 is located at a hedgehog spin-vortex crystal antiferromagnetic quantum critical point which is avoided due to superconductivity. The discovery of the magnetic quantum criticality without nematicity in CaK(Fe1?xNix)4As4 suggests that the spin fluctuations are the primary driver of superconductivity."

Furukawa's discovery was a collaboration between Ames Laboratory's world-leading SSNMR team and the lab's condensed matter physicists, including Paul Canfield, a senior scientist at Ames Laboratory and a Distinguished Professor and the Robert Allen Wright Professor of Physics and Astronomy at Iowa State University.

"This is a new type of magnetic order," said Canfield. "You have this interesting interaction between superconductivity and magnetism from high temperatures in the normal state. This gives us some sense that this high temperature superconductivity may be coming from this near quantum critical antiferromagnetic transition."

Research Report: "Hedgehog Spin-vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 revealed by NMR"

Related Links
DOE/Ames Laboratory
Powering The World in the 21st Century at Energy-Daily.com

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

Ben-Gurion University researchers achieve breakthrough in process to produce hydrogen fuel
New York NY (SPX) Oct 30, 2018
Ben-Gurion University of the Negev (BGU) and the Technion Israel Institute of Technology researchers have cracked the chemical mechanism that will enable development of a new and more efficient photo-chemical process to produce hydrogen fuel from water, according to a new paper published in Nature Communications. The team is the first to successfully reveal the fundamental chemical reaction present in solar power that could form the missing link to generate the electricity necessary to accomplish ... read more