Flux Growth of Trilayer La₄Ni₃O₁₀ Single Crystals at Ambient Pressure

Rare earth nickelates are of significant interest due to their emerging physical properties such as high-temperature superconductivity, multiferroicity, metal-insulator transition, charge and spin order, etc. However, single-crystal growth of these nickelates remains a central challenge. Here, single crystals of the trilayer nickelate La4Ni3O10 with dimensions up to 182 mu m were successfully grown for the first time using K2CO3 as a flux at ambient pressure. The as-grown crystals crystallize in the P2(1)/a space group at room temperature and exhibit a first-order metal-to-metal transition, as evidenced by resistivity, magnetic susceptibility, and DSC. The successful growth of La4Ni3O10 single crystals at ambient pressure provides an alternative and easy-to-access method without the need of high pressure for the growth of other interesting rare earth nickelate single crystals, including the newly discovered high-temperature superconductor La3Ni2O7.