Imagine a future with batteries that do not need to be charged, electric cars at more affordable prices, highly efficient electric motors and cheaper electric energy due to the ease of transmission and storage. Gaining a deeper understanding 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 electric current without resistance and, therefore, without loss of energy. In Brazil, about 7.5% of electrical energy is lost in transmission and distribution, as the materials in 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 common combustion-powered cars, still lose up to 15% of energy when charging batteries. 

Given the importance of this field, the Brazilian Center for Research in Energy and Materials (CNPEM), an organization supervised by the Ministry of Science, Technology and Innovation (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 help of super potent X-rays generated by Sirius. 

This is because, although superconducting materials were discovered in 1911 – and are already widely used, such as in magnetic resonance imaging machines and scientific equipment – science still does not fully understand their occurrence. “A general understanding of the phenomenon of superconductivity is possibly the biggest open question in the field of condensed matter physics”, ponders Narcizo Marques Souza Neto, researcher and Head of the Condensed Matter and Materials Science Division at the National Light Laboratory. Synchrotron (LNLS/CNPEM). 

Another challenge in the area, in which CNPEM has been active, is the search for superconducting materials that operate at temperatures that are increasingly close to room temperature. This is because currently, a major limitation for the use of superconducting materials on a large scale is the need to be kept at very low temperatures, very close to absolute zero (-273.15°C), which requires their association with large cooling infrastructures. Thus, a superconducting material capable of operating at room temperature would allow an extremely low cost for all electricity applications, as there would be no losses due to electrical resistance. 

Room temperature 

In research recently published in the journal Frontiers in Electronic Materials, CNPEM researcher Audrey Grockowiak, together with collaborators from Germany and the USA, demonstrated the existence of a material that presents superconductivity at temperatures of about 277°C (550 K) when subjected to at high pressures, an important milestone in the century-old search for a superconducting material capable of operating outside of cryogenic (extremely cold) temperatures. 

This material is composed of hydrogen atoms and lanthanum, an element of the rare earth family, but quite common in the earth’s crust. According to Audrey, “when subjected to extremely high pressures – nearly two million times the atmospheric pressure at sea level, or the equivalent of half the pressure in the Earth’s core – these elements form a compound with superconducting properties at a temperature well above ambient temperature”. 

These very high pressures are achieved in a special device that fits in the palm of the hand, called a diamond anvil cell. This equipment makes it possible to “squeeze” a tiny sample of material, smaller than a fraction of the thickness of a hair, between two diamonds, and thus subject it to pressures comparable to what is found in the core of planet Earth. 

According to the researcher, there is still a long way to go before this material has commercial applications, especially due to the need to keep it under extremely high pressures. “We are currently in the discovery stage. Our next step, which may still take a long time, is to try to reproduce what happened in the material under extremely high pressures (2 million atmospheres) under ambient conditions (1 atmosphere, for example), to discover ways to scale this material”, he explains. 

Originally, Audrey Grockowiak’s research was carried out on synchrotron light sources outside Brazil: The Advanced Photon Source, in the USA, PETRA III, in Germany, and ESRF, in France. Now, the researcher works with the Ema beamline team, one of the research stations for the Sirius synchrotron light source, at CNPEM, and she should carry out her next experiments here. 

Gordon and Betty Moore Community Grant 

Recently, Audrey Grockowiak and partner researchers received funding from the North American Gordon and Betty Moore Community Foundation to train a new generation of experimental researchers in quantum materials in high pressure techniques, to support the discovery of new high-temperature superconductors rich in hydrogen. 

Its main objective is to strengthen ties between the quantum and high-pressure materials communities, through the organization of two workshops. One will train scientists in high-pressure techniques, and the other will seek to bring together researchers from diverse backgrounds to form a diverse community prepared to better understand this new family of superconductors. In addition, each researcher will receive grants for their research in ambient temperature superconductors for industrial application purposes. 

Serrapilheira 

In 2018, researcher Narcizo Marques Souza Neto was one of those approved in the 1st public call for the Serrapilheira Institute (a non-profit private institution dedicated to funding scientific projects), with the project “A look at X-rays in superconductivity”. Since then, he has been researching new spectroscopic techniques to study materials under extreme conditions, looking for superconducting materials at room temperature. 

Using the high-brightness X-rays produced at Sirius, the group will have the best conditions ever developed for the search for new candidate materials for the position of superconductors. “The idea is to use the unique capabilities of high-intensity X-ray beams in nanometer sizes available in Sirius’ Ema beamline to try to microscopically understand the effect of superconductivity and observe it at room temperature,” explains Narcizo. 

In 2019, the Serrapilheira Institute grant was renewed, with the application of resources for research and for the integration and training of people from groups underrepresented in science. 

Ema Beamline 

The Ema beamline (Extreme condition Methods of Analysis) is one of the most advanced resources for experiments looking for solutions for technologies involving superconductivity. The research station was designed to study materials subjected to extremely high temperatures, over 8000°C, or extremely low temperatures, close to absolute zero, or also at extremely high pressures, equivalent to twice the pressure at the center of the Earth. 

“When matter is subjected to these extreme conditions, it can present new physical and chemical properties, changing, for example, from conductor to insulator, from magnetic to non-magnetic, and vice versa, or even present characteristics that do not exist under normal conditions, as is the case with superconducting materials”, explains Ricardo Reis, a researcher at the LNLS who coordinates the Ema beamline. 

Such conditions can only be unraveled by a high-brightness X-ray beam, such as the one produced by Sirius, from the combination of several techniques, such as diffraction, absorption spectroscopy and inelastic X-ray scattering. In the Ema line it will be possible to answer questions about the atomic structure of materials and how they change according to the extremely low temperature or very high-pressure conditions required during the manufacturing process of a superconducting material. 

At the end of January, the first successful experiments were carried out on the Ema beamline, and soon, another two beamlines from Sirius will allow investigations in superconductivity. One of them is the Ipê line (Inelastic scattering and Photoelectron spectroscopy), which allows the characterization of the chemical composition, electronic structure, and elemental excitations in several materials, and is currently in the testing phase. And the other is the Sapê light line (Angle-resolved Photoemission), aimed at analyzing the electronic structure of crystalline materials, which is in an advanced stage of assembly.