From Synthesis to Superconductivity: Hands-On Learning of Quantum Materials through YBCO Doping

In the advancement of quantum materials research, consistent follow-up content in science education becomes paramount. In this article, we report how the synthesis and characterization of the high-temperature superconductor, yttrium barium copper oxide (YBCO), can effectively address this concern. Our exploration encompasses the comparison between pristine YBCO samples and La-, Ce-, and Fe-doped variants to examine the emergence and suppression of superconductivity. Magnetic levitation experiments under liquid nitrogen conditions revealed the presence of the flux pinning effect in La- and Ce-doped samples, whereas it was absent in Fe-doped samples, consistent with temperature-dependent resistance measurements. X-ray diffraction analysis confirmed that La atoms successfully substituted for the Y site, while Ce atoms remain incompatible with the YBCO phase under our synthesis conditions. In contrast, when Fe atoms replace the Cu site, they suppress the superconductivity and transform the crystal structure from orthorhombic to tetragonal. We suggest that our study not only provides insights into the physical properties of YBCO through introducing various dopants but also serves as a benchmark for educators developing analogous or extended experiments.