Crystal structure and magnetic properties of MnxBi100−x (x=48, 50, 55 and 60) compounds

MnxBi100−x (x=48, 50, 55 and 60) alloys were prepared by the induction melting technique, and subjected to melt spinning and subsequent ball milling. XRD shows that the as-milled powders were mainly composed of LTP MnBi. Increasing melt spinning speed and reducing annealing treatment time can restrain the segregation of Mn from MnBi liquid during the peritectic reaction, which increases the LTP MnBi content. High energy ball milling results in the coercivity increase of MnBi powders. With increasing milling time, the coercivity increases initially and then decreases gradually. After ball milling for 4 h, the coercivity of the MnxBi100−x powders is 11.4 kOe for x=48 and 14.8 kOe for x=55. The optimal composition of Mn48Bi52 with more LTP has an M2.2 T of 49.98 emu/g and an Mr of 33.57 emu/g.

► The optimal composition is Mn48Bi52 with more LTP MnBi.
► Melt spinning and annealing process are effective for getting more LTP MnBi.
► Mn48Bi52 exhibits a coercivity of 11.4 kOe.