Making new layered superconductors using high entropy alloys

May 4, 2018, Tokyo Metropolitan University
Schematic image of the crystal structure of high-entropy-alloy-type REO0.5F0.5BiS2. Credit: Yoshikazu Mizuguchi

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 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 . They were able to combine five different rare earth (RE) elements, lanthanum, cerium, praseodymium, neodymium, and samarium, and create a "high alloy" in the blocking layer. High entropy have attracted considerable attention in recent years for their toughness, resistance to fatigue and ductility, amongst many other notable physical properties.

The team's new materials, with different proportions of REs (10 to 30 percent), exhibited enhanced superconducting properties; in particular, materials with the same period in their molecular structure exhibited a superconducting transition at higher temperatures when the blocking layer contained a high entropy alloy. They believe that the high entropy alloy helps to stabilize the crystal structure of the superconducting layer.

The work's impact is not limited to the new materials they present. Given the existence of a large number of superconducting layers which are compatible with RE oxides, this innovation opens the way for a broad new strategy for engineering new, revolutionary superconducting .

Explore further: Team takes the guesswork out of discovering new high-entropy alloys

More information: Ryota Sogabe et al, Superconductivity in REO0.5F0.5BiS2 with high-entropy-alloy-type blocking layers, Applied Physics Express (2018). DOI: 10.7567/APEX.11.053102

Related Stories

Some superconductors can also carry currents of 'spin'

April 16, 2018

Researchers have shown that certain superconductors—materials that carry electrical current with zero resistance at very low temperatures—can also carry currents of 'spin'. The successful combination of superconductivity ...

Recommended for you

How a particle may stand still in rotating spacetime

May 25, 2018

When a massive astrophysical object, such as a boson star or black hole, rotates, it can cause the surrounding spacetime to rotate along with it due to the effect of frame dragging. In a new paper, physicists have shown that ...

Long live the doubly charmed particle

May 25, 2018

Finding a new particle is always a nice surprise, but measuring its characteristics is another story and just as important. Less than a year after announcing the discovery of the particle going by the snappy name of Ξcc++ (Xicc++), ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.