海森堡蔡型近似物中普适旋转磁有序的崩溃
Breakdown of Universal Whirling Order in a Heisenberg Tsai-Type Approximant
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中文总结 AI 辅助
该研究通过X射线共振磁散射测量发现，海森堡与非海森堡Au-Al-R近似物虽晶体结构、磁能标相近，但因自旋各向异性不同，呈现不同磁有序，海森堡极限下普适旋转磁有序崩溃。
中文摘要 AI 辅助
非共面旋转磁有序最近被提出作为非海森堡蔡型准晶近似物中的普适磁态。本文对海森堡和非海森堡Au-Al-R（R=Gd、Tb）1/1近似物进行X射线共振磁散射测量，揭示海森堡极限下该普适性的明显崩溃。非海森堡Au-Al-Tb系统可由此前确定的旋转磁结构很好描述，而海森堡Au-Al-Gd对应物呈现出与普适旋转有序模型不符的、性质不同的方位角依赖关系。尽管晶体结构几乎相同且磁能标相当，两个系统仍稳定出具有相同传播矢量k=(1,0,0)的不同反铁磁基态，表明旋转有序的表观普适性并非仅源于蔡团簇几何，还需要自旋各向异性。这些结果进一步揭示海森堡极限下出现了一组近简并的竞争磁态流形。
英文摘要
Noncoplanar whirling magnetic order has recently been proposed as a universal magnetic state in non-Heisenberg Tsai-type quasicrystal approximants. Here, X-ray resonant magnetic scattering measurements on Heisenberg and non-Heisenberg Au-Al-R (R = Gd, Tb) 1/1 approximants reveal a clear breakdown of this universality in the Heisenberg limit. While the non-Heisenberg Au-Al-Tb system is well described by the previously identified whirling magnetic structure, the Heisenberg Au-Al-Gd counterpart exhibits qualitatively different azimuthal-angle dependences that are incompatible with the universal whirling-order model. Despite nearly identical crystal structures and comparable magnetic energy scales, the two systems stabilize distinct antiferromagnetic ground states with the same propagation vector k = (1, 0, 0), demonstrating that the apparent universality of whirling order is not a consequence of Tsai-cluster geometry alone but requires spin anisotropy. These results further reveal the emergence of a competing manifold of nearly degenerate magnetic states in the Heisenberg limit.
