Intrinsically weak magnetic anisotropy of cerium in potential hard-magnetic intermetallics
Intrinsically weak magnetic anisotropy of cerium in potential hard-magnetic intermetallics
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DOI：
10.1038/s41535-020-00301-6
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发表时间：
2021-01-05
影响因子：
5.7
通讯作者：
Pourovskii, Leonid, V
中科院分区：
文献类型：
--
作者：
Galler, Anna;Ener, Semih;Pourovskii, Leonid, V
铈基金属间化合物作为现有的含有稀有重稀土元素的高性能磁体的可能替代品，目前吸引了很多兴趣。然而，由于近藤效应的定量描述的困难，Ce在这些系统中的固有磁性知之甚少，近藤效应是一种多体现象，传导电子屏蔽了Ce-4f矩。在这里，我们表明，Ce-Fe金属间化合物中的Ce-4f壳是部分近藤屏蔽。近藤规模显着提高氮化合物抑制Ce-4f的磁各向异性的贡献，在显着的对比氮化的效果在含其他稀土元素的同构金属间化合物。我们确定了完整的温度依赖性的Ce-4f单离子各向异性，并表明，即使未屏蔽的Ce-4f矩贡献不大的室温内禀磁硬度。因此，我们的研究建立了基于铈的永磁金属间化合物的潜力的基本限制。
Cerium-based intermetallics are currently attracting much interest as a possible alternative to existing high-performance magnets containing scarce heavy rare-earth elements. However, the intrinsic magnetic properties of Ce in these systems are poorly understood due to the difficulty of a quantitative description of the Kondo effect, a many-body phenomenon where conduction electrons screen out the Ce-4f moment. Here, we show that the Ce-4f shell in Ce-Fe intermetallics is partially Kondo screened. The Kondo scale is dramatically enhanced by nitrogen interstitials suppressing the Ce-4f contribution to the magnetic anisotropy, in striking contrast to the effect of nitrogenation in isostructural intermetallics containing other rare-earth elements. We determine the full temperature dependence of the Ce-4f single-ion anisotropy and show that even unscreened Ce-4f moments contribute little to the room-temperature intrinsic magnetic hardness. Our study thus establishes fundamental constraints on the potential of cerium-based permanent magnet intermetallics.