Effects of Sn addition on the microstructure and magnetic properties of MnBi bulk magnets

Abstract The Sn addition MnBi bulk magnets with high density and superior coercivity (Hc) were prepared by hot compaction. It was found that the added Sn was dispersed between the MnBi particles as an intergranular phase. The appropriate intergranular phase content could be beneficial in improving the Hc due to the strong magnetic isolation effects. The Hc of the MnBi/Sn bulk magnet was increased from 8.6 kOe to 11.5 kOe as the Sn addition contents were increased in the range of 0 wt.% to 5 wt.%. A relatively high squareness (Mr/Ms) of 0.91 was obtained for the 1 wt.% Sn addition Mn56Bi44 bulk magnet exhibiting the maximum energy product (BH)max of 7.8 MGOe with high Hc of 10 kOe at room temperature.