Effect of Sb and In doped on microstructure and magnetic properties of melt-spun MnBi nanocrystalline alloys

The effect of dual-element Sb and In doped on MnBi nanocrystalline alloys was systematically investigated by comparing the states in both as-spun and annealed conditions. An annealing duration of 3 h at 573 K for Mn55Bi45 ribbons resulted in a purity of 96.5 wt% and a saturation magnetization (Ms) of 70.7 emu/g. Additionally, the introduction of SbIn-doped at a concentration of 1.5 at.% resulted in the formation of a metal intermetallic compound, the MnBi0.9Sb0.1 phase, within the nanocrystalline MnBi alloy. The Sb-In doping concentration was increased from 0 at.% to 1.5 at.%, and the coercivity (Hc) in the MnBi annealed ribbons was increased from 3.2 kOe to 7.2 kOe, while Mr/Ms was increased from 49.7 % to 62.2 %. The significant refinement in grain size observed in the SbIn-doped MnBi annealed ribbons, which reached the submicron crystallinity range, was attributed to these enhancements in Hc and Mr/Ms.