Magnetic state of EuN: X-ray magnetic circular dichroism at the Eu M4,5 and L2,3 absorption edges
Magnetic state of EuN: X-ray magnetic circular dichroism at the Eu M4,5 and L2,3 absorption edges
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DOI：
10.1103/physrevb.83.174404
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发表时间：
2011-05-02
影响因子：
3.7
通讯作者：
Meyer, C.
中科院分区：
文献类型：
--
作者：
Ruck, B. J.;Trodahl, H. J.;Meyer, C.
本文报道了用M-4，M-5-和L-2，L-3边x射线磁性圆二色谱研究了一氮化铕中Eu的离子比磁极化。两边的吸收光谱表明，主要信号来自Eu3+，而Eu2+价态的贡献很小(类似于2%)，我们认为Eu2+价态与少量的N空位有关。在4f和5d轨道以及两个价态都观察到了磁极化。M-4，M-5边XMCD信号的温度和场依赖关系显示出Eu3+的van Vleck特征(主要的Eun贡献)和少量Eu2+离子的布里渊顺磁信号。此外，L-2，L-3的边缘表明，Eu3+离子具有5d轨道，这些轨道既被离子内f-d交换极化，也被相邻Eu~(2+)离子间d-d交换极化。在低至10K的温度下，没有证据表明Eu离子之间存在磁序。
We report M-4,M-5-and L-2,L-3-edge x-ray magnetic circular dichroism (XMCD) studies of the ion-specific magnetic polarization on Eu in europium mononitride. The absorption spectra at both edges show a main signal originating from Eu3+ with a well-separated small (similar to 2%) contribution from a Eu2+ valence state that we propose is associated with a small concentration of N vacancies. Magnetic polarization is observed in both 4f and 5d orbitals and for both valence states. The temperature and field dependence of the M-4,M-5-edge XMCD signal shows a van Vleck signature from Eu3+ (main EuN contribution) and a Brillouin paramagnetic signal from the small concentration of Eu2+ ions. In addition, the L-2,L-3 edge shows that the Eu3+ ions have 5d orbitals that are polarized both by intra-ion f-d exchange and by inter-ionic d-d exchange from neighboring Eu2+ ions. There is no evidence of magnetic order among the Eu ions at temperatures as low as 10 K.