Electronic structure and possible martensitic transformation in Mn₂NiGe and?Ni₂MnGe

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• 作者：Hongzhi Luo^a ; ^b ; ^{hongzhi_luo@yahoo.com.cn} ; ^{luo_hongzhi@163.com} ; Fanbin Meng^a ; Guodong Liu^a ; Heyan Liu^a ; Pengzhong Jia^a ; Enke Liu^b ; Wenhong Wang^b ; Guangheng Wu^b
• 关键词：A. Magnetic intermetallics ; B. Magnetic properties ; B. Martensitic transformations ; E. Ab-initio calculations
• 刊名：Intermetallics
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：38
• 期：Complete
• 页码：139-143
• 全文大小：718 K

文摘

The electronic structure and magnetism of Heusler alloys Mn₂NiGe and Ni₂MnGe have been studied by first-principles calculations. The possible non-modulated tetragonal martensitic transformation in them has been predicted. For both Mn₂NiGe and Ni₂MnGe, the tetragonal martensitic phase is lower in energy compared with the cubic austenitic phase. In Ni₂MnGe, the martensitic transformation follows the conservation of volume. But in Mn₂NiGe, a small contraction of the martensitic cell volume is predicted. The energy difference ¦¤E between the martensitic and austenitic phase is??8?meV/cell in Ni₂MnGe and??80?meV/cell in Mn₂NiGe, so it is more likely to observe martensitic transformation in Mn₂NiGe or Heusler alloys with similar compositions. Ni₂MnGe is found to be a ferromagnet, while Mn₂NiGe is a ferrimagnet in which the Mn spin moments are in antiparallel coupling.