Mössbauer Spectroscopy Studies on Magnetic Properties for 57Fe-substituted Ni-Mn-Sn Metamagnetic Shape Memory Alloys

Metals

Rie Y. Umetsu²  Kenji Sano³  Kouji Fukushima³  Takeshi Kanomata¹  Yusuke Taniguchi⁴  Yasushi Amako⁴ 

[1] Research Institute for Engineering and Technology, Tohoku Gakuin University, Tagajo 985-8537, Japan; E-Mail:;Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan; Japan Science and Technology Agency-Precursory Research for Embryonic Science and Technology (JST-PREST), Tokyo 102-0076, Japan;Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537, Japan; E-Mails:;Faculty of Science, Shinshu University, Matsumoto 390-8621, Japan; E-Mails:

关键词: metamagnetic shape memory alloy;    mössbauer spectroscopy;    heusler alloy;    martensitic transformation;    austenite phase;   

DOI  :  10.3390/met3020225

来源: mdpi

【 摘 要 】

In order to investigate the Fe substituted effects on the magnetic properties of the Ni-Mn-Sn metamagnetic shape memory alloys, magnetization and the Mössbauer spectroscopy measurements were carried out with using ⁵⁷Fe-doped specimens of Ni₂Mn_1.48−x⁵⁷Fe_xSn_0.52 (x = 0.02, 0.04 and 0.08). Singlet-type Mössbauer spectra were clearly observed for x = 0.02 and 0.04 just below the martensitic transformation temperature, T_M, and above the Curie temperature, T_C, in the austenite phase. It was clear that the magnetic state in the martensite phase just below T_M was paramagnetic for x = 0.02 and 0.04. In further doped ⁵⁷Fe to Ni₂Mn_1.48Sn_0.52, T_C in the austenite phase slightly increased. However, the value of T_M significantly decreased. As a result, martensite phase with small spontaneous magnetization directly transformed to the ferromagnetic austenite phase during heating for x = 0.08. These results obtained from the Mössbauer spectra were consistent with the results of the magnetic measurements in this study and the phase diagram reported by Fukushima et al. for normal Fe-doped Ni₂Mn_1.48−xFe_xSn_0.52 alloys. The breakdown of the general rule, in which the ferromagnetic shape memory alloys with larger value of the valence electrons per atom, e/a, showed higher T_M, was also appeared in Ni₂Mn_1.48−xFe_xSn_0.52 alloys, being similar to Ni₂Mn_1−xFe_xGa alloys.

【 授权许可】

CC BY   
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