Advances in understanding superconducting material

Superconductivity has the potential to revolutionize technology, whether in lossless power transmission, more efficient electric motors and other applications. Recently these investigations have gained a new ally: Sirius

Imagine a future with batteries that don’t need charging, electric cars at more affordable prices, highly efficient electric motors and cheaper electricity due to ease in their transmission and storage. Gaining a deeper knowledge of the phenomenon of superconductivity is the key to this true technological revolution, which would have a potential impact on all types of electrical equipment.  

This is because superconductivity is the property that allows certain materials to conduct electrical current without resistance and therefore without loss of energy. In Brazil, about 7.5% of electricity is lost in transmission and distribution, since the materials of these systems dissipate part of the energy, for example, in the form of heat. Also electric cars, even though they are much more efficient than ordinary combustion-powered cars, still lose up to 15% of the energy when charging batteries.  

In view of the importance of this field, the National Center for Research in Energy and Materials (CNPEM), an organization supervised by the Ministry of Science, Technology of Innovations (MCTI), has been actively working to advance the understanding of the phenomenon of superconductivity. One of the research fronts in this area seeks to develop new tools for the experimental study of the physical phenomenon of superconductivity with the aid of superpotent X-rays generated by Sirius. 

Read more on the Sirius website

Image: The Ema light line is one of the most advanced scientific tools for experiments seeking solutions for technologies involving superconductivity

Triggering room-temperature superconductivity with light

Scientists discover that triggering superconductivity with a flash of light involves the same fundamental physics that are at work in the more stable states needed for devices, opening a new path toward producing room-temperature superconductivity.

Much like people can learn more about themselves by stepping outside of their comfort zones, researchers can learn more about a system by giving it a jolt that makes it a little unstable – scientists call this “out of equilibrium” – and watching what happens as it settles back down into a more stable state.

In the case of a superconducting material known as yttrium barium copper oxide, or YBCO, experiments have shown that under certain conditions, knocking it out of equilibrium with a laser pulse allows it to superconduct – conduct electrical current with no loss – at much closer to room temperature than researchers expected. This could be a big deal, given that scientists have been pursuing room-temperature superconductors for more than three decades.

But do observations of this unstable state have any bearing on how high-temperature superconductors would work in the real world, where applications like power lines, maglev trains, particle accelerators and medical equipment require them to be stable?

A study published in Science Advances today suggests that the answer is yes.

“People thought that even though this type of study was useful, it was not very promising for future applications,” said Jun-Sik Lee, a staff scientist at the Department of Energy’s SLAC National Accelerator Laboratory and leader of the international research team that carried out the study.

Read more on the SLAC website

Image: To study superconducting materials in their “normal,” non-superconducting state, scientists usually switch off superconductivity by exposing the material to a magnetic field, left. SLAC scientists discovered that turning off superconductivity with a flash of light, right, produces a normal state with very similar fundamental physics that is also unstable and can host brief flashes of room-temperature superconductivity. These results open a new path toward producing room-temperature superconductivity that’s stable enough for practical devices.

Credit: Greg Stewart/SLAC National Accelerator Laboratory

Green information technologies: Superconductivity meets Spintronics

Superconducting coupling between two regions separated by a one micron wide ferromagnetic compound has been proved by an international team. This macroscopic quantum effect, known as Josephson effect, generates an electrical current within the ferromagnetic compound made of superconducting Cooper-pairs. Magnetic imaging of the ferromagnetic region at BESSY II has contributed to demonstrate that the spin of the electrons forming the Cooper pairs are equal. These results pave the way for low-power consumption superconducting spintronic-applications where spin-polarized currents can be protected by quantum coherence.

When two superconducting regions are separated by a strip of non-superconducting material, a special quantum effect can occur, coupling both regions: The Josephson effect. If the spacer material is a half-metal ferromagnet novel implications for spintronic applications arise. An international team has now for the first time designed a material system that exhibits an unusually long-range Josephson effect: Here, regions of superconducting YBa2Cu3O7 are separated by a region of half-metallic, ferromagnetic manganite (La2/3Sr1/3MnO3) one micron wide.

Read more on the HZB website

Image: Device where the long range Josephson coupling has been demonstrated.  Superconducting YBa2Cu3Oregions (yellow) are separated by a half-metal La2/3Sr1/3MnO3 ferromagnet (green).

Credit: © Nature Materials 2021: 10.1038/s41563-021-01162-5

First light at Furka: The experiments can begin

It’s another milestone on the path to full operation of the X-ray free-electron laser SwissFEL with five experiment stations in all: “First light” at the experiment station Furka. It clears the way for experimental possibilities that are unique worldwide. Team leader Elia Razzoli explains what the Furka Group is planning to do.

Why is “first light” such an important occasion for your team?

Elia Razzoli: It means we’re in business. Or to be more specific: Now we can begin working on the first experiments.

The general public might imagine that you simply flip a switch, and then the light is there. But presumably it’s not that simple in your case . . .

No, it is a complex task. When we at SwissFEL talk about light, we do not mean visible light, but rather X-ray light with characteristics that are unique in the world. To generate that light, and for research to be able to use it, several teams at PSI have to work together. With the Furka experiment station we are, so to speak, at the end of the food chain. To generate the X-ray light of SwissFEL, electrons must be forced onto a sinuous track with the aid of magnets. In the process, they emit the X-ray light that we need to carry out the actual investigations. The magnets that redirect the electrons in this way are called undulators. And they are precisely what makes the whole thing so difficult, because they have to work exactly in sync; otherwise the X-ray light doesn’t have the quality that we need. The complexity of the system grows exponentially with the number and length of the undulators. That is why first light at Furka is already a masterful technical and organisational feat.

Read more on the PSI website

Image: Members of the team that achieved the milestone at the Furka station of SwissFEL: Eugenio Paris (left), Elia Razzoli, Cristian Svetina (right)

Credit: Paul Scherrer Institute/Mahir Dzambegovic

Understanding the physics in new metals

Researchers from the Paul Scherrer Institute PSI and the Brookhaven National Laboratory (BNL), working in an international team, have developed a new method for complex X-ray studies that will aid in better understanding so-called correlated metals. These materials could prove useful for practical applications in areas such as superconductivity, data processing, and quantum computers. Today the researchers present their work in the journal Physical Review X.

In substances such as silicon or aluminium, the mutual repulsion of electrons hardly affects the material properties. Not so with so-called correlated materials, in which the electrons interact strongly with one another. The movement of one electron in a correlated material leads to a complex and coordinated reaction of the other electrons. It is precisely such coupled processes that make these correlated materials so promising for practical applications, and at the same time so complicated to understand.

Strongly correlated materials are candidates for novel high-temperature superconductors, which can conduct electricity without loss and which are used in medicine, for example, in magnetic resonance imaging. They also could be used to build electronic components, or even quantum computers, with which data can be more efficiently processed and stored.

Read more on the BNL website

Image: Brookhaven Lab Scientist Jonathan Pelliciari now works as a beamline scientist at the National Synchrotron Light Source II (NSLS-II), where he continues to use inelastic resonant x-ray scattering to study quantum materials such as correlated metals.

Credit: Jonathan Pelliciari/BNL