High-temperature superconductivity is reported in a series of compositionally complex cuprates with varying degrees of size and spin point-defect disorder. Three compositions of Y-site alloyed ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$, i.e., (5Y)BCO, were prepared via solid-state methods using different sets of rare earth ions on the Y site. Synchrotron x-ray diffraction and energy-dispersive x-ray spectroscopy confirm these samples have high phase purity and homogeneous mixing of the Y-site elements. For samples near optimal doping, electrical resistivity and magnetometry measurements reveal the superconducting transition temperature, $T_C$, is greater than 91 K for all 5Y alloying compositions. The lack of $T_C$ suppression observed in these materials, of order $1\%$ relative to pure YBCO ($T_C=93$ K), contrasts recent results on other multicomponent cuprates based on the La-214 system where superconductivity was not observed. Therefore, a key result from this work is the demonstration that high-temperature superconductivity can exist in complex ceramic compositions. The difference in superconducting behavior between these compositionally complex cuprate families is discussed in terms of impurity potentials and sample form (powder vs film). This work sets the stage for future studies to leverage the larger composition and disorder phase space of compositionally complex cuprates to isolate different types of disorder and their effect on the various electronic phases exhibited by high-$T_C$ superconductors.

• Received 21 September 2023
• Accepted 16 January 2024

DOI:https://doi.org/10.1103/PhysRevMaterials.8.024801