Spontaneous Magnetization and Magnon-TA Phonon Interaction during the Premartensitic Transformation in Ni2 MnGa Alloy
WAN Jian-Feng**
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240
Abstract ：The magnetic anomaly associated with the premartensitic transformation (PT) in Heusler alloy Ni2 MnGa is investigated by using the Green's function technique based on the magnon-TA phonon interaction. The results of the numerical calculations suggest that the magnetic anomaly during the PT may originate from the strong magnon-TA phonon interaction, because this kind of coupling effect will destroy the magnetic ordering in some local zones and reduce the magnetization of the system. Magnon-magnon interaction plays a positive role in enhancing the magnetization and tends to reduce the PT temperature while this kind of interaction has little effect on the characteristic TA phonon-wavevector corresponding to the anomaly of spontaneous magnetization at the PT temperature.
收稿日期: 2012-03-16
出版日期: 2012-10-01
:
63.20.kk
(Phonon interactions with other quasiparticles)
75.60.Ej
(Magnetization curves, hysteresis, Barkhausen and related effects)
64.70.K-
75.10.Dg
(Crystal-field theory and spin Hamiltonians)
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2012, Vol. 29 
