Temperature Dependences of the Electrical Resistivity on the Heusler Alloy System Ni2MnGa1−xFex

Yoshiya Adachi,Xiao Xu,Rie Umetsu,Takeshi Kanomata,Yuki Ogi,Ryosuke Kainuma,Noriaki Kobayashi,Yuki Hayasaka

doi:10.3390/met7100413

Yoshiya Adachi, Xiao Xu + Show 6 more

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https://doi.org/10.3390/met7100413

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Abstract

Temperature dependences of the electrical resistivity have been measured on the Heusler alloy system Ni2MnGa1−xFex. The phase diagram of Ni2MnGa1−xFex was constructed on the basis of the experimental results. The structural and magnetic transition temperatures are consistent with those previously determined by magnetic measurements. The changes of the electrical resistivity at the martensitic transition temperature, ∆ρ, were studied as a function of Fe concentration x. The ∆ρ abruptly increased in the concentration range between x = 0.15 and 0.20. The magnetostructural transitions were observed at x = 0.275, 0.30, and 0.35.

Highlights

IntroductionNi-Mn based ferromagnetic shape memory alloys (FSMAs) with full Heusler-type structure have attracted much attention because of their potential applications in smart materials
Ni-Mn based ferromagnetic shape memory alloys (FSMAs) with full Heusler-type structure have attracted much attention because of their potential applications in smart materials.These Heusler alloys exhibit a giant field-induced shape memory effect, large magnetoresistance, and large magnetocaloric effect [1,2,3,4,5,6]
The martensitic transition temperature TM was defined by the equation: TM = (TMs + TAf )/2, where TMs and TAf are the martensitic transition starting temperature and the reverse martensitic transition finishing temperature, respectively

Summary

Introduction

Ni-Mn based ferromagnetic shape memory alloys (FSMAs) with full Heusler-type structure have attracted much attention because of their potential applications in smart materials. With further increase of x, the magnetostructural transitions between the paramagnetic austenite (Para-A) and the ferromagnetic martensite (Ferro-M) phase occur in limited concentration range. Hayasaka et al determined the phase diagram in the temperature-concentration plane of Ni2 MnGa1–x Fex (0 ≤ x ≤ 0.40) [15]. The characteristics of the determined phase diagram of Ni2 MnGa1–x Fex (0 ≤ x ≤ 0.40) are very similar to those of Ni2+x Mn1–x Ga (0 ≤ x ≤ 0.36) [11,12] and Ni2 Mn1–x Cux Ga (0 ≤ x ≤ 0.4) [10], where the magnetostructural transition between Para-A and Ferro-M occurs. The electric properties are examined experimentally to gain deeper insight into the electronic properties of Ni2 MnGa1–x Fex alloys

Experimental Procedures

Results and Discussion

Thefrom concentration dependence of shown

Conclusions