Precursor effects and premartensitic transformation in Ni2MnGa.
Precursor effects and premartensitic transformation in Ni2MnGa.
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DOI：
10.1103/physrevb.54.15045
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发表时间：
1996-12
期刊：
影响因子：
--
通讯作者：
A. Zheludev;S. M. Shapiro;P. Wochner;Lee E. Tanner
中科院分区：
文献类型：
--
作者：
A. Zheludev;S. M. Shapiro;P. Wochner;Lee E. Tanner
用非弹性中子散射和中子衍射法研究了Ni{sub2}MNGA形状记忆Heusler合金单晶在较宽的温度范围内，包括母相({italT}{gt}{italT}{sub1}=260K)、预马氏体相({italT}{sub1}{gt}{italT}{gt}{italT}{sub{italM})和马氏体区({italT}{lt}{italT}}=220K)。观察到母相中的声子色散曲线出现了几个反常现象。预马氏体相包括对母立方结构的横向调制，其简单周期为(1/3，1/3，0)。低温马氏体的近似四方晶格被无公度波矢({zeta}{sub{italM}}，{zeta}{sub{italM}}，0)，{zeta}{sub{italM}}{Approx_Equity}0.43的横向调制所扭曲。这些观察到的现象归因于电子-声子相互作用和非谐效应。{版权所有}{1996年美国物理学会。}
Inelastic neutron scattering and neutron diffraction were used to study a single crystal of the Ni{sub 2}MnGa shape memory Heusler alloy in a wide temperature range covering the parent phase ({ital T}{gt}{ital T}{sub 1}=260 K), a premartensitic phase ({ital T}{sub 1}{gt}{ital T}{gt}{ital T}{sub {ital M}}), and a martensitic ({ital T}{lt}{ital T}{sub {ital M}}=220 K) phase region. Several anomalies in the phonon dispersion curves in the parent phase were observed. The premartensitic phase involves a transverse modulation of the parent cubic structure with a simple periodicity of (1/3,1/3,0). The approximately tetragonal lattice of the low-temperature martensite is distorted by transverse modulations with incommensurate wave vectors ({zeta}{sub {ital M}},{zeta}{sub {ital M}},0), {zeta}{sub {ital M}}{approx_equal}0.43. The observed phenomena are attributed to electron-phonon interactions and anharmonic effects. {copyright} {ital 1996 The American Physical Society.}