Experimental Study of the time dependences of the martensite transition of novel Heusler alloys in pulsed and steady magnetic fields

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560798
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical properties of metals
• Research Institution: Ryukoku University
• Principal Investigator: SAKON Takuo 龍谷大学, 理工学部, 教授 (80271964)
• Co-Investigator(Renkei-kenkyūsha): ADACHI Yoshiya 山形大学, 工学部, 准教授 (60262416) ; FUJITA Asaya 産総研中部グリーン磁性材料研究センター材料解析, 開発チーム, チーム長 (10323073)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 遍歴電子磁性 / 強磁場磁性 / ホイスラー合金 / 形状記憶合金 / 磁化 / 磁気熱量効果 / 示差熱量測定

Outline of Final Research Achievements

Thermal strain, magnetostriction and magnetization measurements of Ni41Co9Mn31.5Ga18.5 polycrystalline ferromagnetic shape memory alloy (FSMA) were performed.The reverse martensite and martensite transition temperatures (TR, TM) decreased gradually with increasing magnetic field. The field dependence of the TM, dTM/dB, is －4.2 K/T and that of the TR, dTR/dB, is －7.9 K/T. The metamagnetic transition appeared between 330 K and 390 K. The results of giant hysteresis of thermal strain and magnetization indicate that a magneto-structural transition occurred at TM. The region above TM or TR is the ferromagnetic austenite phase and that below TM or TR is the paramagnetic or weak ferromagnetic martensitic phase. At constant temperature, a magnetic field-induced strain was observed with a value of 0.001, which indicates that this alloy is sensitive to magnetic fields. Strong magneto-structural coupling was revealed by the magnetic properties and phase transitions.

Free Research Field

磁性物理学