Reduced spin damping in inverse spinel Mn2TiO4 by ordered occupancy of magnetic ions

•Oxygen-deficient causes that Mn2TiO4 systems show a disorder (Fd-3 m) to order (P4322) structural transition.•The ferromagnetic resonance linewidth of tetragonal Mn2TiO4 is much smaller than that of cubic Mn2TiO4.•The diminution of orbital magnetic moment decreases the spin damping in tetragonal Mn2TiO4. We investigated the ferromagnetic resonance of inverse spinel Mn2TiO4, and found the distortion of oxygen-octahedron caused by ordered occupancy of magnetic ions can effectively reduce magnetic damping of magnetic insulator materials. High-quality cubic and tetragonal Mn2TiO4 single crystals with disordered and ordered occupancy of Mn2+ and Ti4+ at B sites were grown in pure Argon and the mixture of Hydrogen and Argon, respectively. Cubic and tetragonal Mn2TiO4 exhibit the same magnetic behaviors, but the ferromagnetic resonance linewidth of tetragonal Mn2TiO4 is much smaller than that of cubic Mn2TiO4. Moreover, the weaker spin–orbit coupling is, the smaller g-factor and then the narrower ferromagnetic resonance linewidth are in Mn2TiO4 systems, suggesting the decrease of spin damping in tetragonal Mn2TiO4 originates from the diminution of orbital magnetic moment after distortion of oxygen-octahedron.