Atomic disorder effects on half-metallicity of the full-Heusler alloys Co2(Cr1-xFex)Al:: A first-principles study -: art. no. 144413

We investigate the atomic disorder effects on the half-metallicity of the full-Heusler alloy Co-2(Cr1-xFex)Al from first principles by using the Korringa-Kohn-Rostoker method with the coherent potential approximation. Our results show that disorder between Cr and Al does not significantly reduce the spin polarization of the parent alloy Co2CrAl, while disorder between Co and Cr makes a considerable reduction of the spin polarization. It is observed that the spin polarization of Co-2(Cr1-xFex)Al decreases with increasing Fe concentration x in both the ordered L2(1) and the disordered B2 structures, and that the effects of the disorder on the spin polarization is significant at low Fe concentrations. The results suggest that a highly spin-polarized ferromagnet with high Curie temperature will be obtained if a Co-2(Cr1-xFex)Al with the ordered L2(1) structure can be fabricated at low Fe concentrations.

我们通过使用相干势近似的科林加 - 科恩 - 罗斯托克（Korringa - Kohn - Rostoker）方法从第一性原理研究了原子无序对全赫斯勒合金Co₂(Cr₁₋ₓFeₓ)Al半金属性的影响。我们的结果表明，Cr和Al之间的无序不会显著降低母体合金Co₂CrAl的自旋极化，而Co和Cr之间的无序会使自旋极化大幅降低。可以观察到，在有序的L2₁和无序的B2结构中，Co₂(Cr₁₋ₓFeₓ)Al的自旋极化都随着Fe浓度x的增加而降低，并且在低Fe浓度下无序对自旋极化的影响显著。结果表明，如果能在低Fe浓度下制备出具有有序L2₁结构的Co₂(Cr₁₋ₓFeₓ)Al，将会得到一种具有高居里温度的高自旋极化铁磁体。