Magnetic properties of single-phase MnBi grown from MnBi{sub 49} melt

The single-phase NiAs-type MnBi, embedded in Bi matrix, was grown from homogeneous MnBi{sub 49} melt at low temperatures to prevent the formation of Mn{sub 1.08}Bi. An abrupt magnetization change was observed at ∼240 K. The origin of this change was ascribed to the movement of the Mn atoms between the regular sites and the interstitial sites in the MnBi lattices. The splitting of the x-ray photoelectron lines of MnBi indicates the presence of two binding states of Mn atoms, one of which was ascribed to interstitial Mn atoms. A large coercivity up to 1.79 T at 400 K was observed in the as-grown bulk isotropic MnBi alloys.