日本东京科技大学R. Tamura团队实现了准晶中反铁磁有序性的观察。相关论文发表在2025年4月14日出版的《自然—物理学》杂志上。

准晶是具有非典型旋转对称性的长程有序材料，如5倍、10倍或12倍对称性，这与晶体学周期性不相容。尽管在准晶中观察到了类似自旋玻璃的冻结现象，但反铁磁序却没有。研究组报告了二十面体准晶Au₅₆In_28.5Eu_15.5中反铁磁有序的实验证据。其磁化曲线在6.5 K的Néel温度下显示出尖锐的尖点，在此温度下的变质磁异常和比热异常都与反铁磁转变一致。

在低于Néel温度的中子衍射数据中出现的磁布拉格反射进一步证实了这种二十面体准晶中的长程反铁磁序。该发现解决了反铁磁序在真实准晶中是否可能的长期问题，特别是对反铁磁二十面体准晶和准周期磁序的进一步研究，而不是凝聚态物理学中通常的周期磁序。

附：英文原文

Title: Observation of antiferromagnetic order in a quasicrystal

Author: Tamura, R., Abe, T., Yoshida, S., Shimozaki, Y., Suzuki, S., Ishikawa, A., Labib, F., Avdeev, M., Kinjo, K., Nawa, K., Sato, T. J.

Issue&Volume: 2025-04-14

Abstract: Quasicrystals are long-range-ordered materials with atypical rotational symmetries, such as 5-fold, 10-fold or 12-fold symmetries, which are incompatible with crystallographic periodicity. Although spin-glass-like freezing phenomena have been observed in quasicrystals, antiferromagnetic order has not. Here we report experimental evidence for antiferromagnetic order in the icosahedral quasicrystal Au₅₆In_28.5Eu_15.5. Its magnetization curve shows a sharp cusp at a Néel temperature of 6.5K, and both metamagnetic anomaly below and specific heat anomaly at this temperature are consistent with an antiferromagnetic transition. The appearance of magnetic Bragg reflections in the neutron diffraction data below the Néel temperature further confirms the long-range antiferromagnetic order in this icosahedral quasicrystal. Our discovery resolves the long-standing issue of whether antiferromagnetic order is possible in real quasicrystals, inviting further studies particularly on antiferromagnetic icosahedral quasicrystals and quasiperiodic magnetic order, as opposed to periodic magnetic order generally in condensed-matter physics.

DOI: 10.1038/s41567-025-02858-0

Source: https://www.nature.com/articles/s41567-025-02858-0