Magnetic properties and structural phase transformations of NiMnGa alloys

Author

Wang, W.H. ; Hu, F.X. ; Chen, J.L. ; Li, Y.X. ; Wang, Z. ; Gao, Z.Y. ; Zheng, Y.F. ; Zhao, L.C. ; Wu, G.H. ; Zan, W.S.

Author_Institution

Inst. of Phys., Acad. Sinica, Beijing, China

Volume

37

Issue

4

fYear

2001

fDate

7/1/2001 12:00:00 AM

Firstpage

2715

Lastpage

2717

Abstract

The magnetic properties and structural phase transformations of Heusler alloys Ni_2+xMn_1-xGa and Ni_2-xMn _1+x/2Ga_1+x/2 were investigated. It was found that the martensitic transformation temperature increases and the Curie temperature decreases with decreasing Mn concentration in the Ni_2+xMn_1-xGa system, but the magnetic properties decrease faster than those do in the Ni_2-xMn_1+x/2Ga_1+x/2 system. This suggests that the influence of the conduction electron concentration and the distance between Mn atoms on the Curie temperature is stronger than the magnetic dilution effect. The martensitic transformation temperature shows a peak value at x=0.06 in the Ni_2-xMn_1+x/2Ga _1+x/2 system. A large stress-free magnetic-field-induced strain (MFIS) of 1.8% has been obtained at room temperature in a single crystal sample with the composition of the first system

Keywords

Curie temperature; electron density; exchange interactions (electron); ferromagnetic materials; gallium alloys; magnetic susceptibility; magnetisation; magnetomechanical effects; manganese alloys; martensitic transformations; nickel alloys; 300 K; Curie temperature; Heusler alloys; MFIS; Mn concentration; Mn-Mn atom distance; Ni₂MnGa; NiMnGa alloys; conduction electron concentration; magnetic dilution effect; martensitic transformation temperature; stress-free magnetic-field-induced strain; structural phase transformations; Iron alloys; Magnetic field induced strain; Magnetic materials; Magnetic properties; Materials science and technology; Nickel alloys; Saturation magnetization; Shape memory alloys; Strain measurement; Temperature sensors;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.951284

Filename

951284