Researchers from Tokyo Metropolitan University have created new superconductors made of layers of bismuth sulfide (BiS2) and a high-entropy rare earth alloy oxyfluoride, containing five rare earth (RE) elements at the same crystallographic site. The new material retains superconducting properties over a wider range of lattice parameters than materials without high-entropy alloy states.
Their work promises an exciting new strategy for designing new layered superconductors, a potentially key development in the search for high-temperature superconductors.
Superconductors are key to a range of exciting potential applications. For example, zero resistivity promises loss-free power transmission and powerful electromagnets. The challenge has been to discover a material that retains this property at higher temperatures, closer to ambient temperatures. Despite focused work and a number of breakthroughs in recent years, the hunt is still on for effective strategies to create new superconducting materials.
One strategy is the use of layered materials with a molecular structure consisting of alternating superconducting layers and “blocking layers” acting as insulating spacers. A team led by Associate Professor Yoshikazu Mizuguchi from the Department of Physics, Tokyo Metropolitan University, has uncovered an important aspect of designing the insulating layer. They were able to combine five different rare earth (RE) elements, lanthanum, cerium, praseodymium, neodymium, and samarium, and create a “high entropy alloy” in the blocking layer. High entropy alloys have attracted considerable attention in recent years for their toughness, resistance to fatigue and ductility, amongst many other notable physical properties.
Read more: Making new layered superconductors using high entropy alloys
Find the paper here: Superconductivity in REO0.5F0.5BiS2 with high-entropy-alloy-type blocking layers
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