High-Pressure Synthesis of Lu₂NiIrO₆ with Ferrimagnetism and Large Coercivity

Double-perovskite Lu₂NiIrO₆ was synthesized at high pressure (6 GPa) and high temperature (1300 °C). Synchrotron powder X-ray diffraction indicates that its structure is a monoclinic double perovskite (space group P2₁/ n) with a small, 11% Ni/Ir antisite disorder. X-ray absorption near-edge spectroscopy measurements established Ni²⁺ and Ir⁴⁺ formal oxidation states. Magnetic studies indicate a ferrimagnetic transition at 207 K. The low-temperature magnetization curve of Lu₂NiIrO₆ features broad hysteresis with a coercive field as high as 48 kOe. These results encourage the search for hard magnets in the class of 3d/5d double-perovskite oxides.