Single crystal growth of nickelates for potential high-Tc superconductors

Recently, superconductivity was discovered in two different structural types of nickelates. To study them in detail, we grew large crystals. In the case of nickelate single crystals with infinite repeating layers, it was shown that the absence of superconductivity is most likely due to the limited solubility of the doping. In addition, we found several crystallographic phases in single crystals of La₃Ni₂O₇. They show a pronounced sensitivity to oxygen stoichiometry, which explains their physical properties and the significant pressure dependence of superconductivity.