High-temperature superconductors represent a unique class of materials capable of conducting electric current without resistance at significantly higher temperatures compared to conventional superconductors – often even at the temperature of liquid nitrogen (77 K). These materials have a wide range of applications in modern technologies, from lossless power transmission to magnetic levitation and quantum computing. One of the most important and widely studied high-temperature superconductors is yttrium barium copper oxide (YBa2Cu3O7-x abbreviated as YBCO). This ceramic material belongs to the group of so-called cuprate superconductors and is well known for its ability to enter the superconducting state at temperatures around 92 K.
However, working with YBCO is challenging because it is a chemically reactive material sensitive to changes in its internal structure Even minor deviations due to temperature, pressure, humidity or contamination can lead to significant changes in its superconducting properties. Such changes are mostly undesirable in industry as well as in research. In our study, we focused on the effect of chemical solvents on the properties of YBCO. Among the investigated substances, dichloromethane (DCM) was of particular interest as it showed a prominent reactivity with the YBCO surface. We found that part of the chlorine from DCM diffused into the surface layers of the YBCO structure. This process caused a positive rearrangement in the internal structure of the material, leading to an unexpected increase in the critical temperature.
Authors: M. Bennár, M. Španková, M. Talacko, M. Gregor, J. Kronek, Š. Chromik
Link: https://doi.org/10.1007/s10854-024-13243-7