Ab initio predictions for the effect of disorder and quarternary alloying on the half-metallic properties of selected Co2Fe-based Heusler alloys
Ab initio predictions for the effect of disorder and quarternary alloying on the half-metallic properties of selected Co2Fe-based Heusler alloys
复制标题
DOI：
10.1088/0953-8984/19/32/326216
复制
发表时间：
2007-08-15
影响因子：
2.7
通讯作者：
Hono, K.
中科院分区：
文献类型：
--
作者：
Gercsi, Z.;Hono, K.
Co2Fe 基霍斯勒合金具有高居里温度和磁化强度，因此它们是自旋电子学应用中研究最多的成分。在这里，我们报告了从头计算，以研究结构无序对三元 Co2.25-xFe0.75+xSi 合金中理论自旋极化和磁化强度的影响。还研究了在 Co2FeSi 成分中用 Mn 或 Cr 代替 Fe 以及逐渐用 Al 或 Ga 代替 Si 的四元 Heusler 合金。对于高铁浓度合金，如果在计算中考虑到小的现场库仑交换，则保留斯莱特-鲍林规则。在这种情况下，发现通过合金化改变价电子总数是调整半金属行为的有效方法，具有高抗结构紊乱能力。还讨论了这些合金中现场关联对于正确描述磁性和电子结构的必要性。
Co2Fe-based Heusler alloys possess high Curie temperatures and magnetization, therefore they are the most studied compositions for spintronics applications. Here we report ab initio calculations to investigate the effect of structural disorder on the theoretical spin polarization and magnetization in ternary Co2.25-xFe0.75+xSi alloys. Quarternary Heusler alloys with substitution of Mn or Cr for Fe, and gradual replacement of Si by Al or Ga in the Co2FeSi composition, were also studied. For high Fe concentration alloys, the Slater-Pauling rule is preserved if a small on-site Coulomb exchange is taken into account in the calculations. In such a case, the change in the total number of valence electrons by alloying was found to be an efficient way to tailor the half-metallic behavior with high resistance against structural disorder. The necessity of the on-site correlation in these alloys to the correct description of magnetic and electronic structure is also addressed.