Researchers at the Goethe University in Frankfurt have discovered an important mechanism for superconductivity in a metallic compound containing ytterbium, rhodium and silicon.
Researchers at the Goethe University have discovered an important mechanism for superconductivity in a metallic compound containing ytterbium, rhodium and silicon. As reported by Cornelius Krellner and his colleagues in the current edition of the "Science" journal, the underlying concept of the quantum-critical point has long been discussed as a possible mechanism for high-temperature superconductivity.
Confirming this in YbRh2Si2 after 10 years of extensive research is thus a milestone in basic research. Due to its extremely low transition temperature of two-thousandths of a degree above absolute zero, the material will have no practical relevance.
"The ytterbium atoms are essential to the material properties because they are magnetic – and for a particularly fascinating reason", Prof. Krellner from the Institute for Physics at Goethe University explains. This is because the transition to the magnetized state (phase transition) takes place at such low temperatures that temperature-related movements of the tiny atomic magnets no longer play a role.
This is what distinguishes this phase transition from all other known transitions, such as the freezing of water into ice. Quantum fluctuations dominate at temperatures near absolute zero (minus 273 degrees). These are so strong that nature attempts to take on alternative ordered fundamental states.
Superconductivity is a potential collective state which can arise at a quantum-critical point. "After we discovered it in YbRh2Si2, we were able to show that unconventional superconductivity is a general mechanism at a quantum-critical point", Krellner explains. The elaborate low-temperature measurements were taken in collaboration with the Walther-Meißner Institute for Low Temperature Research in Garching.
Cornelius Krellner studied YbRh2Si2 10 years ago while working towards his doctorate at the Max-Planck Institute for Chemical Physics of Solids. At the time, he was growing single crystals of the compound. The quality and size of these was essential to measuring the material properties in the first place.
"We were all very enthusiastic when we saw the first indications of superconductivity, and I put all my efforts into growing even better and larger single crystals", remembers Krellner, who has headed the Crystal and Materials Laboratory at Goethe University since 2012.
That it took so long after that to produce the final proof of unconventional superconductivity was due to the fact that the measurements are extremely time-consuming. Furthermore, it was necessary to study the superconductivity with different techniques in order to show that it really was a case of unconventional superconductivity.
Krellner and his team use a special method to grow the crystals. It prevents ytterbium from vaporizing at the required high temperatures of 1500 degrees Celsius. "We are currently the only ones in Europe with the capability of producing single crystals of YbRh2Si2" Krellner is proud to tell us.
Over the next few years, he and his colleagues want to study the magnetic order above the superconducting range. Physicists will also study the superconductivity itself in greater detail over the next few years – a task which will be enabled by the pure and large single crystals from AG Krellner.
Pictures are available for downloading here: (We will insert a link)
Publication: E. Schuberth et al., Emergence of Heavy-Electron Superconductivity by the Ordering of Nuclear Spins. Science (2016).
Information: Prof. Dr. Cornelius Krellner, Institute of Physics, Phone.: (069) 798-47295, email@example.com.
Goethe University has a strong background in research and is based in the European financial center of Frankfurt. Founded in 1914 with purely private funds by liberally-oriented Frankfurt citizens, it is dedicated to research and education under the motto "Science for Society" and to this day continues to function as a "citizens’ university". Many of the early benefactors were Jewish. Over the past 100 years, Goethe University has done pioneering work in the social and sociological sciences, chemistry, quantum physics, brain research and labour law. It gained a unique level of autonomy on 1 January 2008 by returning to its historic roots as a "foundation university". Today, it is among the top ten in external funding and among the top three largest universities in Germany, with three clusters of excellence in medicine, life sciences and the humanities.
Publisher: The President of Goethe University, Editor: Dr. Anne Hardy, Contact for Science Communications, Marketing and Communications Department, Theodor-W.-Adorno-Platz 1, 60629 Frankfurt am Main, Phone: +49(0)69 798-12498, Fax: (069) 798-761 12531, firstname.lastname@example.org.
Dr. Anne Hardy | idw - Informationsdienst Wissenschaft
Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen
New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy