School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK.
School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
Phys Chem Chem Phys. 2022 May 4;24(17):10451-10464. doi: 10.1039/d2cp00648k.
The rapid development of applications relying on magnetism at the nanoscale has put a spotlight on nanoparticles with novel morphologies that are associated with enhanced electronic and magnetic properties. In this quest, nanoalloys combining highly magnetic cobalt and weakly reactive gold could offer many application-specific advantages, such as strong magnetic anisotropy. In the present study, we have employed density functional theory (DFT) calculations to provide a systematic overview of the size- and morphology-dependence of the energetic order and magnetic properties of AuCo nanoparticles up to 2.5 nm in diameter. The core-shell icosahedron was captured as the most favourable morphology, showing a small preference over the core-shell decahedron. However, the magnetic properties (total magnetic moments and magnetic anisotropy) were found to be significantly improved within the L1 ordered structures, even in comparison to monometallic Co nanoparticles. Atom-resolved charges and orbital moments accessed through the DFT analysis of the electronic level properties permitted insight into the close interrelation between the AuCo nanoparticle morphology and their magnetism. These results are expected to assist in the design of tailored magnetic AuCo nanoalloys for specific applications.
依赖于纳米尺度磁性的应用的迅速发展，使得具有新型形态的纳米粒子成为焦点，这些纳米粒子具有增强的电子和磁性特性。在这一探索中，结合了高磁性钴和弱反应性金的纳米合金可能会带来许多特定于应用的优势，例如强磁各向异性。在本研究中，我们采用了密度泛函理论（DFT）计算，对直径达 2.5nm 的 AuCo 纳米粒子的能量有序性和磁性特性的尺寸和形态依赖性进行了系统的概述。我们发现，核壳二十面体是最有利的形态，其优先性略高于核壳十面体。然而，即使与单金属 Co 纳米粒子相比，在 L1 有序结构中，磁性特性（总磁矩和磁各向异性）也得到了显著改善。通过对电子能级特性的 DFT 分析获得的原子分辨电荷和轨道矩，使我们能够深入了解 AuCo 纳米粒子形态与其磁性之间的密切关系。这些结果有望有助于设计针对特定应用的定制磁性 AuCo 纳米合金。
