High-Temperature Ferrimagnetism Driven by Lattice Distortion in Double Perovskite Ca2FeOsO6

5d and 3d hybrid solid-state oxide Ca2FeOsO6 crystallizes into an ordered double-perovskite structure with a space group of P2(1)/n with high-pressures and temperatures. Ca2FeOsO6 presents a long-range ferrimagnetic transition at a temperature of similar to 320 K (T-c) and is not a band insulator, but is electrically insulating like the recently discovered Sr2CrOsO6 (Tc similar to 725 K). The electronic stat of Ca2FeOsO6 is adjacent to a half-metallic state as well as that of Sr2CrOsO6. In addition, the high-T-c ferrimagnetism was driven by lattice distortion, which was observed for the first time among double-perovskite oxides and represents complex interplays between spins and orbitals. Unlike conventional ferrite and garnet, the interplays likely play a pivotal role of the ferrimagnetism. A new class of 5d-3d hybrid ferrimagnetic insulators with high-T-c is established to develop practically and scientifically useful spintronic materials.