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
μm were successfully grown for the first time using K2CO3 as a flux at ambient pressure. The as-grown crystals
crystallize in the P21/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.