TY - JOUR
T1 - Forced magnetostrictions and magnetizations of Ni2+xMnGa1-x at its curie temperature
AU - Sakon, Takuo
AU - Hayashi, Yuhi
AU - Li, Dexin
AU - Honda, Fuminori
AU - Oomi, Gendo
AU - Narumi, Yasuo
AU - Hagiwara, Masayuki
AU - Kanomata, Takeshi
AU - Eto, Tetsujiro
N1 - Funding Information:
Okamoto and Fumihiko Morioka of Ryukoku University for helping to create the apparatus. This project is partly supported by the Ryukoku Extension Center (REC) at Ryukoku University. This research was carried out in part at the International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University. This research was also carried out at the Center for Advanced High Magnetic Field Science in Osaka University under the Visiting Researcher’s Program of the Institute for Solid State Physics, the University of Tokyo.
Funding Information:
The authors thank Mitsuo Kataoka for helpful discussions. The authors also thank Mitsuo Okamoto and Fumihiko Morioka of Ryukoku University for helping to create the apparatus. This project is partly supported by the Ryukoku Extension Center (REC) at Ryukoku University. This research was carried out in part at the International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University. This research was also carried out at the Center for Advanced High Magnetic Field Science in Osaka University under the Visiting Researcher's Program of the Institute for Solid State Physics, the University of Tokyo. This research was founded by Visiting Researcher's Program of the Institute for Solid State Physics, the University of Tokyo.
Publisher Copyright:
© 2018 by the authors.
PY - 2018/10/28
Y1 - 2018/10/28
N2 - Experimental investigations into the field dependence of magnetization and the relationship between magnetization and magnetostriction in Ni2+xMnGa1-x (x = 0.00, 0.02, 0.04) alloy ferromagnets were performed following the self-consistent renormalization (SCR) spin fluctuation theory of itinerant ferromagnetism. In this study, we investigated the magnetization of and magnetostriction on Ni2+xMnGa1-x (x = 0.02, 0.04) to check whether these relations held when the ratio of Ni to Ga and, the valence electron concentration per atom, e/a were varied. When the ratio of Ni to Ga was varied, e/a increased with increasing x. The magnetization results for x = 0.02 (e/a = 7.535) and 0.04 (e/a = 7.570) suggest that the critical index δ of H ∝ Mδ is around 5.0 at the Curie temperature TC, which is the critical temperature of the ferromagnetic-paramagnetic transition. This result confirms Takahashi's spin fluctuation theory and the experimental results of Ni2MnGa. The spontaneous magnetization pS slightly decreased with increasing x. For x = 0.00, the spin fluctuation parameter in k-space (momentum space; TA) and that in energy space (T0) were obtained. The relationship between peff/pS and TC/T0 can also be explained by Takahashi's theory, where peff indicates the effective magnetic moments. We created a generalized Rhodes-Wohlfarth plot of peff/pS versus TC/T0 for other ferromagnets. The plot indicates that the relationship between peff/pS and T0/TC follows Takahashi's theory. We also measured the magnetostriction for Ni2+xMnGa1-x (x = 0.02, 0.04). As a result, at TC, the plot of the magnetostriction (ΔL/L) versus M4 shows proportionality and crosses the origin. These magnetization and magnetostriction results were analyzed in terms of Takahashi's SCR spin fluctuation theory. We investigated the magnetostriction at the premartensite phase, which is the precursor state to the martensitic transition. In Ni2MnGa system alloys, the maximum value of magnetostriction is almost proportional to the e/a.
AB - Experimental investigations into the field dependence of magnetization and the relationship between magnetization and magnetostriction in Ni2+xMnGa1-x (x = 0.00, 0.02, 0.04) alloy ferromagnets were performed following the self-consistent renormalization (SCR) spin fluctuation theory of itinerant ferromagnetism. In this study, we investigated the magnetization of and magnetostriction on Ni2+xMnGa1-x (x = 0.02, 0.04) to check whether these relations held when the ratio of Ni to Ga and, the valence electron concentration per atom, e/a were varied. When the ratio of Ni to Ga was varied, e/a increased with increasing x. The magnetization results for x = 0.02 (e/a = 7.535) and 0.04 (e/a = 7.570) suggest that the critical index δ of H ∝ Mδ is around 5.0 at the Curie temperature TC, which is the critical temperature of the ferromagnetic-paramagnetic transition. This result confirms Takahashi's spin fluctuation theory and the experimental results of Ni2MnGa. The spontaneous magnetization pS slightly decreased with increasing x. For x = 0.00, the spin fluctuation parameter in k-space (momentum space; TA) and that in energy space (T0) were obtained. The relationship between peff/pS and TC/T0 can also be explained by Takahashi's theory, where peff indicates the effective magnetic moments. We created a generalized Rhodes-Wohlfarth plot of peff/pS versus TC/T0 for other ferromagnets. The plot indicates that the relationship between peff/pS and T0/TC follows Takahashi's theory. We also measured the magnetostriction for Ni2+xMnGa1-x (x = 0.02, 0.04). As a result, at TC, the plot of the magnetostriction (ΔL/L) versus M4 shows proportionality and crosses the origin. These magnetization and magnetostriction results were analyzed in terms of Takahashi's SCR spin fluctuation theory. We investigated the magnetostriction at the premartensite phase, which is the precursor state to the martensitic transition. In Ni2MnGa system alloys, the maximum value of magnetostriction is almost proportional to the e/a.
KW - Ferromagnetic Heusler alloy
KW - Itinerant electron magnetism
KW - Magnetization
KW - Magnetostriction
KW - Premartensite phase
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U2 - 10.3390/ma11112115
DO - 10.3390/ma11112115
M3 - Article
AN - SCOPUS:85055721058
SN - 1996-1944
VL - 11
JO - Materials
JF - Materials
IS - 11
M1 - 2115
ER -