The Forced Magnetostrictions and Magnetic Properties of Ni2MnX (X = In, Sn) Ferromagnetic Heusler Alloys

Takuo Sakon; Junya Yamazaki; Takumi Komori; Takeshi Kanomata; Yasuo Narumi; Masayuki Hagiwara; Hiroyuki Nojiri; Yoshiya Adachi

doi:10.3390/ma13092017

The Forced Magnetostrictions and Magnetic Properties of Ni₂MnX (X = In, Sn) Ferromagnetic Heusler Alloys

Materials (Basel). 2020 Apr 25;13(9):2017. doi: 10.3390/ma13092017.

Authors

Takuo Sakon¹, Junya Yamazaki¹, Takumi Komori¹, Takeshi Kanomata², Yasuo Narumi³, Masayuki Hagiwara³, Hiroyuki Nojiri⁴, Yoshiya Adachi⁵

Affiliations

¹ Department of Mechanical and Systems Engineering, Faculty of Science and Technology, Ryukoku University, Otsu 520-2194, Shiga, Japan.
² Research Institute for Engineering and Technology, Tohoku Gakuin University, Tagajo 985-8537, Miyagi, Japan.
³ Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan.
⁴ Institute for Materials Research, Tohoku University, Sendai 980-8577, Miyagi, Japan.
⁵ Graduate School of Science and Engineering, Yamagata University, Yonezawa 992-8510, Yamagata, Japan.

Abstract

Experimental studies into the forced magnetostriction, magnetization, and temperature dependence of permeability in Ni₂MnIn and Ni₂MnSn ferromagnetic Heusler alloys were performed according to the spin fluctuation theory of itinerant ferromagnetism proposed by Takahashi. We investigated the magnetic field (H) dependence of magnetization (M) at the Curie temperature T_C, and at T = 4.2 K, which concerns the ground state of the ferromagnetic state. The M-H result at T_C was analyzed by means of the H versus M⁵ dependence. At 4.2 K, it was investigated by means of an Arrott plot (H/M vs. M²) according to Takahashi's theory. As for Ni₂MnIn and Ni₂MnSn, the spin fluctuation parameters in k-space (momentum space, T_A) and that in energy space (frequency space, T₀) obtained at T_C and 4.2 K were almost the same. The average values obtained at T_C and 4.2 K were T_A = 342 K, T₀ = 276 K for Ni₂MnIn and T_A = 447 K, T₀ = 279 K for Ni₂MnSn, respectively. The forced magnetostriction at T_C was also investigated. The forced linear magnetostriction (ΔL/L) and the forced volume magnetostriction (ΔV/V) were proportional to M⁴, which followed Takahashi's theory. We compared the forced volume magnetostriction ΔV/V and mechanical parameter, bulk modulus K. ΔV/V is inversely proportional to K. We also discuss the spin polarization of Ni₂MnIn and other magnetic Heusler alloys. The p_C/p_S of Ni₂MnIn was 0.860. This is comparable with that of Co₂MnGa, which is a famous half-metallic alloy.

Keywords: ferromagnetic Heusler alloy; itinerant ferromagnetism; magnetization; magnetostriction; spin polarization.