Title :
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
fDate :
7/1/2001 12:00:00 AM
Abstract :
The magnetic properties and structural phase transformations of Heusler alloys Ni2+xMn1-xGa and Ni2-xMn 1+x/2Ga1+x/2 were investigated. It was found that the martensitic transformation temperature increases and the Curie temperature decreases with decreasing Mn concentration in the Ni2+x Mn1-xGa system, but the magnetic properties decrease faster than those do in the Ni2-xMn1+x/2Ga1+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 Ni2-xMn1+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;
Journal_Title :
Magnetics, IEEE Transactions on
