Effects of Ga-doping on the microstructure and magnetic properties of MnBi alloys

The low temperature phase Mn55Bi45-xGax (x = 0, 1, 3, 5, and 10) alloys were prepared by induction melting process with subsequent low temperature annealing. The effects of Ga-doping on the crystal structure and magnetic properties of the alloys were systematically studied. The room temperature coercivities of Mn55Bi45-xGax after ball milling increased from 1.43 T for x = 0 to 1.66 T for x = 5, while the saturation magnetization decreased from 60.7 Am2/kg (x = 0) to 45.1 Am2/kg (x = 5). The maximum energy product (BH)max of Mn55Bi44Ga powders reached 7.87 MGOe. The Curie temperature of the Mn55Bi45-xGax alloys increased from 633 K to 658 K with increasing Ga concentration in the range of 0 ≤ x ≤ 5.