Mazalová Martina, Všianská Monika, Pavlů Jana, Šob Mojmír
Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ611 37 Brno, Czech Republic.
Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, CZ616 62 Brno, Czech Republic.
Nanomaterials (Basel). 2020 Apr 6;10(4):691. doi: 10.3390/nano10040691.
This work presents a comprehensive and detailed ab initio study of interactions between the tilt 5(210) grain boundary (GB), impurities X (X = Al, Si) and vacancies (Va) in ferromagnetic nickel. To obtain reliable results, two methods of structure relaxation were employed: the automatic full relaxation and the finding of the minimum energy with respect to the lattice dimensions perpendicular to the GB plane and positions of atoms. Both methods provide comparable results. The analyses of the following phenomena are provided: the influence of the lattice defects on structural properties of material such as lattice parameters, the volume per atom, interlayer distances and atomic positions; the energies of formation of particular structures with respect to the standard element reference states; the stabilization/destabilization effects of impurities (in substitutional (s) as well as in tetragonal (iT) and octahedral (iO) interstitial positions) and of vacancies in both the bulk material and material with GBs; a possibility of recombination of Si +Va defect to Si one with respect to the Va position; the total energy of formation of GB and Va; the binding energies between the lattice defects and their combinations; impurity segregation energies and the effect of Va on them; magnetic characteristics in the presence of impurities, vacancies and GBs. As there is very little experimental information on the interaction between impurities, vacancies and GBs in nickel, most of the present results are theoretical predictions, which may motivate future experimental work.
这项工作对铁磁镍中倾斜5(210)晶界（GB）、杂质X（X = Al、Si）和空位（Va）之间的相互作用进行了全面而详细的从头算研究。为了获得可靠的结果，采用了两种结构弛豫方法：自动完全弛豫以及相对于垂直于GB平面的晶格尺寸和原子位置寻找最小能量。两种方法得到的结果相当。提供了对以下现象的分析：晶格缺陷对材料结构性质的影响，如晶格参数、每个原子的体积、层间距离和原子位置；相对于标准元素参考态的特定结构的形成能；杂质（处于替代位置（s）以及四方（iT）和八面体（iO）间隙位置）和空位在块状材料以及有GB的材料中的稳定/不稳定效应；Si + Va缺陷相对于Va位置重组为Si缺陷的可能性；GB和Va的形成总能量；晶格缺陷及其组合之间的结合能；杂质偏析能以及Va对其的影响；存在杂质、空位和GB时的磁特性。由于关于镍中杂质、空位和GB之间相互作用的实验信息非常少，目前的大多数结果都是理论预测，这可能会推动未来的实验工作。
