Ab initio studies of disorder in the full Heusler alloy Co2FexMn1-xSi
Ab initio studies of disorder in the full Heusler alloy Co2FexMn1-xSi
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DOI：
10.1063/1.4801745
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发表时间：
2013-05-07
影响因子：
3.2
通讯作者：
Lazarov, V. K.
中科院分区：
文献类型：
--
作者：
Hasnip, P. J.;Smith, J. H.;Lazarov, V. K.
钴基全霍斯勒合金被预测为半金属，在费米能级具有 100% 自旋极化，但这在实践中尚未实现。豪斯勒薄膜通常表现出一定程度的原子无序性，这被认为是基于豪斯勒的自旋阀器件中磁阻较低的原因之一。我们提出了从头算密度泛函理论 + U 研究无序对 Co2Fe0.5Mn0.5Si 电子性能的影响。研究发现，半金属性很大程度上取决于存在的无序类型，当Co亚晶格与Fe/Mn或Si亚晶格混合时，具有低甚至反向的自旋极化，但当Mn/Fe和Si亚晶格混合时，保持高自旋极化。形成能的计算表明，后一种无序是迄今为止最有可能发生的，这是一个令人鼓舞的结果，这意味着可能不需要生产完美有序的赫斯勒合金来实现 100% 自旋极化。 (C) 2013 AIP 出版有限责任公司
Co-based full Heusler alloys have been predicted to be half-metals, with 100% spin polarisation at the Fermi level, yet this has yet to be realised in practice. Heusler thin-films often exhibit a degree of atomic disorder, and this is believed to be one cause of the low magnetoresistance in Heusler-based spin valves' devices. We present an ab initio density functional theory + U investigation into the effect of disorder on the electronic properties of Co2Fe0.5Mn0.5Si. It is found that the half-metallicity depends strongly on the kind of disorder present, with low or even reversed spin-polarisation when the Co sublattice mixes with either the Fe/Mn or Si sublattice, but keeps the high spin polarisation when the Mn/Fe and Si sublattices are mixed. Calculations of the formation energy show that this latter kind of disorder is by far the most likely to occur, an encouraging result which means that it may not be necessary to produce perfectly ordered Heusler alloys in order to achieve 100% spin polarisation. (C) 2013 AIP Publishing LLC