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Selective incorporation of Fe and Co into the Ni2MnGa (001) surfaces: a DFT analysis
Surfaces and Interfaces ( IF 6.2 ) Pub Date : 2022-09-23 , DOI: 10.1016/j.surfin.2022.102367
R. Ponce-Perez, María G. Moreno-Armenta, J. Guerrero-Sánchez

By DFT calculations, we investigated the Co and Fe incorporation into the Ni2MnGa Heusler alloy (001) surface. Calculations consider the Ga-, Ni- and MnGa-terminated surfaces. First-principles thermodynamics was used to determine the stability of the structures. Fe and Co provide selective incorporation into different sites that depend on the growth conditions. For Fe incorporation, four surfaces are stable. High-selectivity was noticed, at Ga-rich and Mn-rich conditions Fe incorporates into Ni sites. From Mn-rich to Mn-poor at Ga-poor conditions, the Mn by Fe substitution is the most stable. At Mn-poor conditions and Ga-intermediate conditions, Fe atoms take on Ga sites. In the case of Co, our stability analysis shows four stable surfaces as well, with similar behavior to the Fe incorporation, since for the region from Mn-rich to Mn-poor at Ga-poor conditions the substitution of Mn by Co is stable; at Ga-rich conditions and from Mn-rich to Mn-intermediated conditions, Co atoms occupy the Ni sites just as in the Fe case. However, in contrast to the Fe case, the Co by Ga substitution is not favorable. Instead, the ideal surfaces appear as the stable structures. Magnetic properties are investigated, finding in all cases a ferromagnetic coupling between the impurities and surface.



中文翻译:

将 Fe 和 Co 选择性掺入 Ni2MnGa (001) 表面:DFT 分析

通过DFT计算,我们研究了Co和Fe掺入Ni 2MnGa Heusler 合金 (001) 表面。计算考虑了以 Ga、Ni 和 MnGa 为终端的表面。第一性原理热力学用于确定结构的稳定性。根据生长条件,Fe 和 Co 可以选择性地掺入不同的位点。对于 Fe 掺入,四个表面是稳定的。注意到高选择性,在富含 Ga 和富含 Mn 的条件下,Fe 结合到 Ni 位点中。在Ga-贫乏条件下从富锰到贫锰,铁取代的锰是最稳定的。在 Mn 贫乏条件和 Ga 中间条件下,Fe 原子占据 Ga 位点。在 Co 的情况下,我们的稳定性分析也显示了四个稳定的表面,具有与 Fe 掺入相似的行为,因为在 Ga 贫乏条件下从富锰到贫锰的区域,用 Co 取代 Mn 是稳定的;在富含 Ga 的条件下以及从富含 Mn 到 Mn 介导的条件下,Co 原子占据 Ni 位置,就像在 Fe 情况下一样。然而,与 Fe 的情况相反,Co 被 Ga 取代是不利的。相反,理想的表面表现为稳定的结构。研究了磁性,在所有情况下都发现杂质和表面之间存在铁磁耦合。

更新日期:2022-09-23
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