A novel type of splayed ferromagnetic order observed in Yb2Ti2O7
A novel type of splayed ferromagnetic order observed in Yb2Ti2O7
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在 Yb2Ti2O7 中观察到一种新型的张开铁磁序
DOI：
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发表时间：
2016
期刊：
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通讯作者：
A. Forget
中科院分区：
文献类型：
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作者：
A. Yaouanc;P. Dalmas de Réotier;L. Keller;B. Roessli;A. Forget
烧绿石绝缘体Yb2Ti2O7近15年来一直受到实验者和理论界的关注。关于低温下可能存在磁布拉格反射的相互矛盾的中子衍射数据已经公布。本文报道了在60mK用中子粉末衍射法观测到的磁布拉格反射。利用表象理论对磁衍射谱进行了分析。我们发现Yb2Ti2O7和Yb2Sn2O7一样是一种张开的铁磁体，从正的居里-魏斯温度推断，Yb2Sn2O7是一种具有主导铁磁相互作用的同胞化合物。然而，垂直于易轴的磁矩分量在Yb2Ti2O7中是全进全出的，而在Yb2Sn2O7中是两进两出的。一幅关于磁性的整体实验图景出现了。
The pyrochlore insulator Yb2Ti2O7 has attracted the attention of experimentalists and theoreticians alike for about 15 years. Conflicting neutron diffraction data on the possible existence of magnetic Bragg reflections at low temperature have been published. Here we report the observation of magnetic Bragg reflections by neutron powder diffraction at 60 mK. The magnetic diffraction pattern is analyzed using representation theory. We find Yb2Ti2O7 to be a splayed ferromagnet as reported for Yb2Sn2O7, a sibling compound with also dominating ferromagnetic interactions as inferred from the positive Curie–Weiss temperature. However, the configuration of the magnetic moment components perpendicular to the easy axis is of the all-in–all-out type in Yb2Ti2O7 while it is two-in–two-out in the Yb2Sn2O7. An overall experimental picture of the magnetic properties emerges.