[15p-A202-1~12] 10.5 Application of magnetic field

▼ [15p-A202-6] Magnetic separation and enrichment of MnBi by solidification in a high magnetic field

〇keisuke suzuki¹, Kensuke Nakazawa¹, Isao Yamamoto¹ (1.Yokohama Nat'l Univ.)

Keywords:magnetic separation, MnBi, magnetic fluid

Magnetic field effects on solidification in a high magnetic field has been reported in many studies. In this study, we focused on MnBi. A sample which has a composition having the same Curie temperature T_c and melting point T_m was solidified in magnetic field to enrich and separate MnBi components.The Mn₁₀Bi₉₀ alloy prepared by arc melting method from 4N-Mn and 5N-Bi was vacuum sealed in a glass tube with a diameter of 8 mm. The alloy was heated up to 632 K for 0.5 h and then vertical magnetic field of up to 5 T was applied. The sample was cooled to 545 K of melting temperature of pure Bi with cooling rate of 0.5 K/min. Large MnBi grains were observed near and outside the sample center for the sample prepared in 3 T. The large grains were aligned direction of the magnetic field of 5 T, and small grains of about 150 μm were arranged in a rod shape. On the other hand, spikes were observed in the vicinity of the circumference of the sample to which 3 T was applied, suggesting the appearance of ferromagnetism in liquid state. The same spikes have been reported only in supercooled Co, however, this is the first observation in binary alloys.