A new nickel-based superconductor exhibits high-quality, high-temperature superconductivity
Superconductivity is a vast playground for scientists in science and engineering. Because superconductors do not have resistance while electrons flow, they are utilized wherever large current or cold environments are required, such as superconducting magnets. Although the concept was introduced more than 100 years ago and is embedded in many technologies today, there are still undiscovered pieces of the puzzle of superconductivity at different temperatures in various materials. After the advent of the first high-temperature superconductor, research on new classes of superconducting compounds has been flourishing. Cuprates, copper-oxide-based compounds with rare-earth ions, have been the major player in high-temperature superconductivity. This is because they become superconducting at higher transition temperatures—the temperatures below which a material has zero electrical resistance.
Nickelates, on the other hand, are the main counterpart to cuprates. Nickelates are not considered as strongly superconducting as cuprates because they tend to have lower transition temperatures, but recent studies from National University of Singapore successfully overturned this expectation. The researchers created an improved nickelate with a transition temperature of 31 Kelvin in ambient pressure, which is the first demonstration of a nickelate achieving a transition temperature comparable to that of a cuprate. One of the breakthroughs in synthesizing this compound was including samarium, a heavy rare-earth element, into the compound. The decision was based on the fact that cuprates tend to have high transition temperatures with larger rare-earth ions. The newly synthesized nickelate had robust superconductivity with the least structural defect.
Discovering a new nickelate stimulates the field because it is different from cuprates in important ways. First, while cuprates conduct electricity mainly within flat layers, the new nickelate material can conduct electricity throughout its entire structure. Second, the rare-earth ion actively provides a mobile electron that enables superconductivity in nickelates. As research on this subject continues, the dream of low-cost, superconductor based technologies for things like MRI and high-efficiency power lines becomes closer to reality.
This study was led by S. Lin Er Chow, et al. from National University of Singapore, Singapore.
Managing Correspondent: Seunghyun (Elizabeth) Park
Press Article: 40-Year Barrier Broken: Scientists discover new high-temperature superconductor (SciTechDaily)
Original Journal Articles: Bulk superconductivity near 40 K in hole-doped SmNiO2 at ambient pressure (Nature)
Image Credit: Julian Litzel (Wikimedia Commons)
