First-principle prediction of half-metallic ferrimagnetism of the Heusler alloys Mn₂CoZ (Z = Al, Ga, Si, Ge) with a high-ordered structure

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• 作者：Naisheng Xing ; Hua Li ; Jianmin Dong ; Run Long ; Changwen Zhang
• 关键词：Heusler alloy ; Electronic structure ; Half-metallic ferrimagnetism ; First-principle calculation
• 刊名：Computational Materials Science
• 出版年：2008
• 期刊代码：31_09270256
• 类别：et
• 出版时间：June 2008
• 卷：42
• 期：4
• 页码：600-605
• 文件大小：425 K

摘要

Using the first-principles plane-wave pseudopotential method within the generalized gradient approximation framework based on density functional theory, we have investigated the electronic structure and magnetism of the Heusler alloys Mn₂CoZ (Z = Al, Ga, Si, Ge) with a high-ordered structure which is similar to the L2₁ structure of the full-Heusler compounds but with different sequence of atoms in the unit cell. It was shown that the high-ordered structural Mn₂CoZ alloys are all ideal half-metallic ferrimagnets at their respective equilibrium lattice constant. They have a total magnetic moment of 2.0 μ_B for Mn₂CoAl (Ga) and 3.0 μ_B for Mn₂CoSi (Ge) per unit cell, respectively. The results are in good agreement with the Slater–Pauling rule. We also found that these alloys maintain half-metallicity within a wide range of lattice constants between 5.4 and 5.9 Å.