Controlled Equilibrium State of Ferromagnetic MnBi by High Magnetic Fields

摘要

Differential thermal analysis (DTA) was carried out for Mn-Bi binary alloys in the temperature range 300-773 K in magnetic fields up to 45 T to investigate the effect of high magnetic fields on the equilibrium state. The decomposition temperature (MnBi→Mn_(1.08)Bi+liquid: 632 K at a zero fields) T_t increases linearly at a rate of 2 KT~(-1) in fields up to 18 T and deviates from the linear increase above 20 T. In addition, the peritectic temperature (Mn_(1.08)Bi→Mn + liquid: 719 K at a zero field) T_m slightly increases by applying magnetic fields. In 45 T, T_t and T_m reach up to 714 K and 723 K, respectively. From detailed investigation using the DTA technique, we obtained the equilibrium phase diagram of the Mn-Bi binary system in a high magnetic field of 15 T.