High-temperature superconductivity is reported in a series of compositionally-complex cuprates with varying degrees of size and spin disorder. Three compositions of Y-site alloyed YBa2Cu3O7−x, i.e., (5Y)BCO, were prepared using solid-state methods with 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. The superconducting phase transition was probed using electrical resistivity and AC magnetometry measurements, which reveal the transition temperature, TC, is greater than 91 K for all series when near optimal oxygen doping. Importantly, these TC values are only ≈1% suppressed relative to pure YBCO (TC = 93 K). This result highlights the robustness of pairing in the YBCO structure to specific types of disorder. In addition, the chemical flexibility of compositionally-complex cuprates allows spin and lattice disorder to be decoupled to a degree not previously possible in high-temperature superconductors. This feature makes compositionally-complex cuprates a uniquely well-suited materials platform for studying proposed pairing interactions in cuprates.
@article{arxiv.2309.12535,
title = {Superconductivity in Compositionally-Complex Cuprates with the YBa$_2$Cu$_3$O$_{7-x}$ Structure},
author = {Aditya Raghavan and Nathan Arndt and Nayelie Morales-Colón and Eli Wennen and Megan Wolfe and Carolina Oliveira Gandin and Kade Nelson and Robert Nowak and Sam Dillon and Keon Sahebkar and Ryan F. Need},
journal= {arXiv preprint arXiv:2309.12535},
year = {2024}
}