Avalon Rare Metals notes that rare metals continue to help scientists and engineers advance much needed material science solutions. “In addition to their many uses in today’s everyday applications, it seems more applications will soon follow!” ‘Spintronics’ is an emerging field of electronics, where devices work by manipulating the spin of electrons rather than the current generated by their motion. High temperature superconductivity is the second advance considered by Avalon.
Rare metal-based samarium hexaboride (SmB6) was instrumental in best understanding the breakthrough spintronics technology. By definition, spintronics, which is occasionally referred to as spinelectronics or fluxtronics, essentially exploits both the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices. As such, this field can offer significant advantages to computer technology.
An intrinsic property of electron spin, is that it gives them their magnetic properties. Spin can take either of two possible states: ‘up’ or ‘down’ (which can be pictured respectively as clockwise or counter-clockwise rotation of the electron around its axis). Spin control can be achieved with materials called ‘topological insulators’. These topological insulators can conduct spin-polarised electrons across their surface with 100% efficiency while the interior acts as an insulator.
One such material, samarium hexaboride (SmB6), has long been theorised to be an ideal and robust topological insulator, but this has never been shown practically. But now scientists from the Switzerland-based Paul Scherrer Institute, the Chinese Academy of Science, and France’s École Polytechnique Fédérale De Lausanne (EPFL) have recently demonstrated experimentally that SmB6 is indeed a topological insulator. Their results were recently published in Nature Communications.
A collaboration between theoretical physicists led by University of Illinois at Chicago (UIC), and experimentalists at Cornell University and Brookhaven National Laboratory have apparently also identified the “quantum glue” that underlies a promising type of superconductivity — the anticipated energy superhighways that conduct electricity without current loss. Superconductivity arises when two electrons in a material become bound together, forming what is called a Cooper pair. The team’s groundbreaking experiments pointed to magnetism as the force underlying the superconductivity in an unconventional superconductor consisting of cerium, cobalt and indium, with the molecular formula CeCoIn5. Rare metals at work again!
As noted by Jeanne Galatzer-Levy, “the earliest superconducting materials required operating temperatures near absolute zero (0o Kelvin, -273oC or −459.67oF). Newer unconventional or ‘high-temperature’ superconductors function at slightly elevated temperatures and seemed to work differently from the first materials. Scientists hoped this difference hinted at the possibility of superconductors that could work at room temperature and be used to create energy superhighways.”
The UIC-Cornell-Brookhaven Team developed high-precision measurements of CeCoIn5 using a scanning tunnelling spectroscopy technique, which apparently addressed two of the long outstanding questions into the relation between the momentum and energy of electrons moving through the material, and the ‘quantum glue’ that binds the electrons into a Cooper pair. They concluded that magnetism is the quantum glue underlying the emergence of unconventional superconductivity in the complex electronic structure CeCoIn5.
The theorists and experimentalists claim they now have an excellent starting point to explore how superconductivity works in other complex material… with a working theory and system that can be studied and tweaked to raise the critical temperature — ideally, all the way up to room temperature.”
