Change of the equilibrium state of ferromagnetic MnBi with high magnetic fields
Differential thermal analysis was carried out on ferromagnetic material MnBi at a temperature range of 300–773K in magnetic fields up to 45T to investigate the effect of high magnetic fields on the decomposition process and corresponding phase diagram. The decomposition temperature Tt (MnBi → Mn1.08 Bi + liquid Bi) increases from 632 K (at a zero field) to 714 K by applying a magnetic field of 45 T. Furthermore, the magnetocaloric effect of MnBi is observed in 11.5–45 T is in the vicinity of 689 K, showing that a field-induced composition process occurs. The obtained results show that the equilibrium state of MnBi can be controlled by using a high magnetic field. (Journal of Alloys and Compounds 509 (2011) L78-L80)
Magnetic-field-induced enhancement for synthesizing ferromagnetic MnBi phase by solid-state reaction sintering
Ferromagnetic MnBi was synthesized using 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. (Journal of Alloys and Compounds 615 (2014) 131-134)
