R-T and R-R exchange interactions in the rare-earth (R)-transition-metal (T) intermetallics : an evaluation from relativistic atomic calculations
R-T and R-R exchange interactions in the rare-earth (R)-transition-metal (T) intermetallics : an evaluation from relativistic atomic calculations
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DOI：
10.1088/0953-8984/3/38/005
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发表时间：
1991-09
期刊：
影响因子：
--
通讯作者：
Hong-shuo Li;Y. P. Li;J. Coey
中科院分区：
文献类型：
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作者：
Hong-shuo Li;Y. P. Li;J. Coey
稀土三价离子的原子内交换积分 J4f-5d、J4f-6s 和 J4f-6p 是通过相对论自洽场原子计算获得的，使用交换势和相关势的局域密度近似。基于简化的三亚晶格（4f、3d和传导电子）平均场模型获得了稀土离子与过渡金属离子之间的有效（分子场）交换系数nRT以及稀土离子之间的nRR。定量结果显示整个稀土系列的 nRT 幅度下降，这与许多稀土过渡金属金属间化合物系列中观察到的值非常吻合。结果表明，4f-5d 交换相互作用比 4f-6s 和 4f-p 相互作用重要得多，正如根据稀土过渡金属间化合物中发生的交换相互作用的 Campbell 模型所预期的那样。
Intra-atomic exchange integrals J4f-5d, J4f-6s and J4f-6p for rare-earth trivalent ions were obtained from relativistic self-consistent field atomic calculations, using the local-density approximation for exchange and correlation potential. The effective (molecular-field) exchange coefficients nRT between rare-earth and transition-metal ions and nRR between rare-earth ions were obtained based on a simplified three-sublattice (4f, 3d and conduction electron) mean-field model. Quantitative results show a decrease in magnitude of nRT across the rare-earth series, which agrees well with values observed in many rare-earth-transition-metal intermetallic series. It is shown that the 4f-5d exchange interaction is far more important than the 4f-6s and 4f-p interactions, as expected from the Campbell model for the exchange interactions occurring in rare-earth-transition-metal intermetallics.