The study on supercooling and solidification process of Mn-based ferromagnets under high magnetic fields

2015 Fiscal Year Final Research Report

• Project/Area Number: 25630268
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Kagoshima University
• Principal Investigator: Koyama keiichi 鹿児島大学, 理工学域理学系, 教授 (70302205)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 金属物性 / 構造機能性材料 / 磁性

Outline of Final Research Achievements

For studying in-field process of melting and solidification visually and quantitatively, in-situ observation system with differential thermal analysis (DTA) utilized in high temperature and high magnetic field was developed. Decomposition processes of the bulk sample of ferromagnetic MnBi were directly observed with collecting DTA data under a high field of 10 T for 290-770 K. When the temperature was over decomposition point (MnBi -> paramagnetic Mn1.08Bi + liquid), liquid phase appeared on the sample surface. When the temperature was over peritectic temperature (~ 700 K: Mn1.08Bi -> Mn + liquid), the sample surface was broken and a large quantity of the liquid phase appeared from the sample. The decomposition temperature increased from 620 K for a zero field to 638 K for a magnetic field of 10 T. A magnetic field effect on the suprcooling state of Mn + liquid -> Mn1.08Bi and MnBi was observed. MnBi bulk magnets were synthesized by heat treatment under a high field.

Free Research Field

磁気物理学