(Fe1-xNix)2P电子结构与磁学特性的X射线近边吸收谱研究

X-ray absorption near-edge structure spectroscopy research on electronic structures and magnetic properties of (Fe_(1-x)Ni_x)_2P

利用X射线近边吸收谱对Fe2P,Ni2P及其掺杂物(Fe1-xNix)2P(x=0·1,0·25,0·5)中Fe,Ni,P的K边进行了研究.结合多重散射理论近边计算,讨论了金属原子不同位置格点3f,3g对近边谱特征的贡献,得出当Ni原子取代Fe原子时将优先占据Fe(3f)格点位置;根据第一性原理对能态的计算发现,不考虑磁性时不同格点P的pDOS未占据态电子结构与P-K近边吸收谱实验相符合;与考虑铁磁性Fe2P的DOS相比较后结果显示Fe2P的磁性主要来源于Fe(3g)格点,铁磁性Ni2P计算的Ni不同格点原子磁矩均接近于0,与它一般显顺磁性结论相一致.

The Fe2P, Ni2P and （Fe1-xNix）2P compounds （x=0.1,0.25,0.5） are studied by X-ray absorption near-edge structure （XANES） spectroscopy at the Fe, Ni and P K-edges. Combined with full multiple-scattering approach calculations of XANES, different contributions of 3f, 3g crystallographic positions to XANES spectra for metal atoms are discussed. It was found that the Ni atom prefers to substitute Fe （3f） sites when introducing Ni atoms. The first-principle density of states calculations were performed and the results show that unoccupied P p-projected DOS of paramagnetic Fe2P and Ni2P are matched with their K-edges XANES spectroscopy. Comparison with DOS calculations for ferromagnetic Fe2P, indicates that the magnetism of Fe2P is mostly due to Fe（3g） sites. The magnetic moments calculated for Ni（3f） and Ni（3g） sites of ferromagnetic Ni2P approach zero, which is in accordance with the conclusion that Ni2P generally appears paramagnetic.