Ab initio calculations of structure and lattice dynamics in Ni-Mn-Al shape memory alloys
Ab initio calculations of structure and lattice dynamics in Ni-Mn-Al shape memory alloys
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DOI：
10.1103/physrevb.70.014111
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发表时间：
2004-07
影响因子：
3.7
通讯作者：
T. Büsgen;J. Feydt;R. Hassdorf;S. Thienhaus;M. Moske;M. Boese;A. Zayak;P. Entel
中科院分区：
文献类型：
--
作者：
T. Büsgen;J. Feydt;R. Hassdorf;S. Thienhaus;M. Moske;M. Boese;A. Zayak;P. Entel
采用密度泛函理论和等离子体波势对磁性形状记忆合金Ni 50 MnxAl 50 −x（0 ≤ x ≤ 50）进行了从头计算。该合金在14 - 31 at.%范围内是铁磁性的MN.从态密度的角度讨论了磁矩和结构性质。此外，还计算了具有长周期洗牌结构的马氏体相：2 M、10 M和14 M。从电子结构和晶格动力学的角度讨论了它们的稳定性，并由此计算了立方L21 Heusler结构[110]方向的声子色散关系。在波矢λ =[1/3 1/3 0]处，横声声子模软化，证实了Ni 2 MnAl在低温下形成调制结构的趋势.调制马氏体相的理论结果对应于实验数据，从薄膜附近的化学计量组成。
Ab initio calculations of the magnetic shape-memory alloy Ni50MnxAl50−x with 0 ≤ x ≤ 50 were carried out using density functional theory and PAW potentials. The alloy is ferromagnetic in the range from 14 to 31 at.% Mn. The magnetic moment and structural properties are discussed in terms of the density of states. Furthermore martensitic phases with long-periodic shuffling structure were calculated: 2M, 10M, and 14M. Their stability is discussed in respect to the electronic structure and the lattice dynamics, whereby phonon dispersion relations in [110] direction for the cubic L21 Heusler structure have been calculated. The transverse-acoustic phonon mode is shown to soften at the wave vector ζ=[1/3 1/3 0] which confirms the tendency of Ni2MnAl to form modulated structures at low temperatures. The theoretical results of the modulated martensitic phases correspond to experimental data, obtained from thin films near the stoichiometric composition.