The discovery could lead to applications in clean energy technologies and the development of superconducting devices such as next-generation computing equipment
Physicists at the University of Bath have discovered a new mechanism that allows magnetism and superconductivity to coexist in the same material. Until now, scientists could only guess how such an unusual coexistence is possible.
This discovery could lead to applications in clean energy technologies and the development of superconducting devices such as next-generation computing equipment.
Generally, superconductivity and magnetism are bad neighbors because the alignment of tiny electronic magnetic particles in ferromagnets usually leads to the destruction of the electron pairs responsible for superconductivity.
Despite this, the researchers found that the iron-based superconductor RbEuFe4As4, which is a superconductor at temperatures below -236 ° C, exhibits both superconductivity and magnetism at temperatures below -258 ° C.
“Some materials have a state where if they are really cold – much colder than Antarctica – they become superconducting. But for this superconductivity to be taken to the next level, at the application level, the material must demonstrate coexistence with magnetic properties. This would allow us to develop magnetic devices, such as magnetic memory and computation using magnetic materials, to also take advantage of superconductivity, ”says David Collomb, who led the study.
“The problem is that superconductivity is usually lost when magnetism is turned on. For many decades, scientists have tried to investigate many materials that have two properties in one material, and material researchers have recently had some success. However, until we understand why coexistence is possible, creating such materials is problematic. ”
“This new study provides us with material with a wide temperature range in which these phenomena coexist, and this will allow us to study in more detail and in detail the interaction between magnetism and superconductivity. Hopefully this will lead us to be able to identify a mechanism through which such coexistence can occur. ”
In a study published in Physical Review Letters, the scientists examined the unusual behavior of RbEuFe4As4 by mapping the magnetic field of a superconducting material as temperatures drop. To their surprise, they found that vortices (points in a superconducting material where a magnetic field penetrates) exhibit marked expansion around -258 ° C, indicating a strong suppression of superconductivity when magnetism is turned on.
These observations are consistent with a theoretical model that describes the suppression of superconductivity by magnetic fluctuations due to europium (Eu) atoms in crystals.
Here, the magnetic direction of each Eu atom begins to oscillate and align with the others when the temperature of the material falls below a certain temperature. This causes the material to become magnetic. The Bath researchers concluded that although superconductivity is significantly weakened by the magnetic effect, it is not completely destroyed – superconductivity and magnetism coexist.
“This suggests that in our material magnetism and superconductivity are kept separate from each other in their own sublattices, which interact only minimally,” said David Collomb.
“This work significantly advances our understanding of rare coexisting phenomena and may lead to possible applications in superconducting devices of the future. This will lead to a deeper search for materials that exhibit both superconductivity and magnetism. We hope this will also encourage researchers to take some of this material and make the next generation of computing devices out of it. ”
“I hope that the scientific community will gradually enter an era where we move from research to creating devices from these materials. In about ten years, we may see prototypes of devices using this technology that will do the real work. ”
The co-authors of this project were Argonne National Laboratory, Hofstra University and Northwestern University.