Electronic structure, magnetism and phase stability of isostructural Ga2MnCo–Ga2MnV Heusler alloys from first principles
Electronic structure, magnetism and phase stability of isostructural Ga2MnCo–Ga2MnV Heusler alloys from first principles
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DOI：
10.1016/j.commatsci.2014.03.050
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发表时间：
2014-06
影响因子：
3.3
通讯作者：
Jiahua Chen;Jiahua Chen;Enke Liu;X. Qi;Hongzhi Luo;Wenhong Wang;Hong-wei Zhang;Shouguo Wang;J. Cai;Guangheng Wu
中科院分区：
文献类型：
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作者：
Jiahua Chen;Jiahua Chen;Enke Liu;X. Qi;Hongzhi Luo;Wenhong Wang;Hong-wei Zhang;Shouguo Wang;J. Cai;Guangheng Wu
用第一性原理计算方法研究了Ga 2基Heusler合金Ga 2 MnCo和Ga 2 MnV的电子结构、磁性和相稳定性。立方Ga_2MnCo和Ga_2MnV的体积守恒四元畸变分别在c/a= 1.17和1.45处显示能量最小值。采用等结构合金化方法，在密度泛函水平上用Co替代V，使两种等结构合金化。计算结果表明，在Ga 2 MnCo-Ga 2 MnV系统中，当热力学驱动力较大，应变能适中时，可能会出现四方马氏体相。对于Ga2MnV0.5Co0.5的中间成分，马氏体和母相之间的能量差达到-140 meV/cell，畸变程度达到c/a= 1.275，这对应于潜在的马氏体相变。计算结果表明，随着c/a的增加，Mn和V原子间的交换作用由反铁磁耦合转变为铁磁耦合.
The electronic structure, magnetism and phase stability of Ga2-based Heusler alloys Ga2MnCo and Ga2MnV are studied by first-principles calculations. The volume-conserving tetragonal distortions of the cubic Ga2MnCo and Ga2MnV show an energy minimum atc/a= 1.17 and 1.45, respectively. The isostructural alloying method is adopted to alloy two isostructures by substituting Co for V at density functional level. The calculations reveal that a potential tetragonal martensite phase can be expected with a large thermodynamic driving force and a moderate strain energy in Ga2MnCo–Ga2MnV system. For the middle composition of Ga2MnV0.5Co0.5, the energy difference between the martensite and parent phase reaches −140 meV/cell and the degree of distortion arrives atc/a= 1.275, which corresponds to a potential martensitic transformation. Based on the calculated results, the exchange interaction between Mn and V atoms is found to change from antiferromagnetic to ferromagnetic coupling with increasingc/a.