Dy在Nd_2Fe_(14)B晶格中的占位及其对Fe原子磁矩影响的第一性原理计算

First-principles calculation of preferential site occupation of Dy ions in Nd_2Fe_(14)B lattice and its effect on local magnetic moments of Fe ions

基于第一性原理投影缀加波和梯度矫正局域密度近似(PAW-GGA),研究了Nd2Fe14B和Dy2Fe14B的基态晶格属性,进而对Dy在Nd2Fe14B晶格中的掺杂进行了研究,并采用GGA+U的方式进行了原子磁矩计算,并与自旋轨道耦合(SOI)计算结果进行了对照.置换计算表明,Dy原子倾向于置换Nd2Fe14B晶格中4f位的稀土原子.磁矩计算表明,在R2Fe14B(R:稀土元素)晶格中,4f位的稀土元素与Fe原子作用更强,对磁性能的影响更大.稀土原子与Fe的作用与距离呈正相关.

The ground states of lattice properties, formation energy and magnetizations of R2Fe14B （R： rare-earth element） were calculated by the first-principles method based on the generalized gradient approximation （PAW-GGA）. GGA＋U method was applied to deal with local magnetic moments from 4f shell of rare-earth elements. Magnetic moments were calculated with and without spin-orbital interactions （SOI）. Site occupation of Dy ions in Nd2FelaB lattice is studied by partial substitution of Dy for Nd on different lattice sites. Calculated substitution energy indicates that the Dy2Fe14B is more stable than Nd2Fe14B and the Dy ions prefer to occupy the 4f sites in NdEFex4B lattice. It is also found that rare-earth ions occupying the 4f sites will interact more strongly with Fe ions and thus show a greater impact on the local magnetization of Fe. The interaction between rare-earth ions and Fe ions is positively correlated with distance.