A research team led by the US Department of Energy’s (DOE) Argonne National Laboratory has found that only half of the atoms of some iron-based superconductors are magnetic, providing a conclusive demonstration of the wave properties of metallic magnetism. in these materials.
The discovery provides insight into the magnetism of certain iron compounds, iron arsenides, and how it helps induce superconductivity, the resistance-free flow of electric current through solid-state material, which occurs at temperatures of up to 138 degrees. Kelvin, or minus -135 degrees Celsius.
“In order to be able to design new superconducting materials, you have to understand what causes superconductivity,” said Raymond Osborn, principal physicist at Argonne, one of the project’s principal investigators. âUnderstanding the origin of magnetism is an essential first step in understanding what makes these materials superconducting. Given the similarity to other materials, such as copper-based superconductors, our goal was to improve our understanding of high temperature superconductivity. “
From an applied point of view, such an understanding would allow the development of magnetic energy storage systems, fast-charging batteries for electric cars and a highly efficient power grid, argonne senior physicist said, Stephan Rosenkranz, the other principal investigator of the project.
Superconductors reduce power losses. The use of high temperature superconducting materials in the power grid, for example, would greatly reduce the large amount of electricity lost as it passes through the grid, allowing the grid to operate more efficiently.
The researchers were able to show that the magnetism of these materials was produced by mobile electrons that are not bound to a particular iron atom, producing waves of magnetization throughout the sample. They discovered that in some iron arsenides, two waves interfere to cancel each other out, producing zero magnetization in some atoms. This quantum interference, never seen before, was revealed by MÃ¶ssbauer spectroscopy, which is extremely sensitive to magnetism at every ferrous site.
The researchers also used advanced photon source high-resolution x-ray diffraction (APS) and spallation neutron source neutron diffraction (SNS) from the Oak Ridge National Laboratory to determine chemical structures and magnetic fields and to map the electronic phase diagram of the samples used. . APS and SNS are facilities for users of the DOE Office of Science.
âBy combining neutron diffraction and MÃ¶ssbauer spectroscopy, we were able to unambiguously establish that this new magnetic ground state has non-uniform magnetization that can only be produced by roaming electrons. These same electrons are responsible for superconductivity, âsaid Rosenkranz.
The research is available in the January 25 online edition of Physics of nature.
Next, Rosenkranz and Osborn plan to characterize magnetic excitations, or fluctuations in iron-based superconductors, to find out how they relate to and eventually cause superconductivity.
Scientists discover microscopic origin of magnetic phase in iron-based superconductors
JM Allred et al. Double Q spin density wave in iron arsenide superconductors, Physics of nature (2016). DOI: 10.1038 / nphys3629
Quote: New Magnetism Research Relates Applications of High Temperature Superconductivity (2016, April 8) Retrieved December 19, 2021 from https://phys.org/news/2016-04-magnetism-high-temp-superconductivity- applications-closer.html
This document is subject to copyright. Other than fair use for private study or research purposes, no part may be reproduced without written permission. The content is provided for information only.