Magnetic-field-induced enhancement for synthesizing ferromagnetic MnBi phase by solid-state reaction sintering

Ferromagnetic MnBi was synthesized by a solid-state reaction sintering method in high magnetic fields up to 15 T. The fraction of ferromagnetic MnBi phase in the sample sintered at 15 T was about 70% by weight, which was much larger than that sintered in a zero magnetic field. It was found that high magnetic fields dramatically enhanced the formation of MnBi phase from bismuth and manganese. In addition, the c-axis of a hexagonal structure of MnBi was oriented parallel to the magnetic field direction. These magnetic field effects on the synthesizing process were examined based on the gain of the Zeeman energy and the uniaxial magnetic anisotropy of MnBi phase.