Quantum magnets based on honeycomb lattices with a low coordination number offer a viable ground to realize exotic emergent quantum excitations and phenomena arising from the interplay between competing magnetic interactions, spin correlations, and spatial anisotropy. However, unlike their low-spin analogs, high-spin honeycomb lattice antiferromagnets have remained comparatively less explored in the context of capturing the classical limits of quantum phenomena. Herein, we report the crystal structure, magnetic susceptibility, specific heat, and electron spin resonance (ESR) measurements, complemented by ab initio density functional theory (DFT) calculations, on polycrystalline samples of FeP3⁢SiO11 in which the Fe3+ ions decorate a nearly perfect 𝑆=52 honeycomb lattice without any site disorder between constituent atoms. Above 150 K, an antiferromagnetic Weiss temperature 𝜃CW=−12K is observed, consistent with DFT calculations, which suggests the presence of strong intraplanar nearest-neighbor and weaker interplanar further neighbor exchange interactions. An anomaly at 𝑇𝑁=3.5K in specific heat and magnetic susceptibility reveals the presence of a long-range ordered ground state in zero field. Above 𝑇𝑁, ESR evidences short-range spin correlations and unsaturated magnetic entropy, while below 𝑇𝑁 unconventional excitations are seen via power-law specific heat. A spin-flop transition is observed at an applied field of 𝜇0⁢𝐻𝑐⁢1=0.2 T. At higher applied fields, 𝑇𝑁 is gradually suppressed down to zero at 𝜇0⁢𝐻c⁢2=5.6T. Above 𝜇0⁢𝐻c⁢2, a broad maximum in specific heat due to gapped magnon excitations indicates the emergence of an interesting nearly polarized state dressed by a disordered state in this honeycomb lattice antiferromagnet.

中文翻译：

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S=52蜂窝状晶格反铁磁体FeP3SiO11中的磁性和场感应效应


基于低配位数蜂窝晶格的量子磁体为实现由竞争性磁相互作用、自旋相关和空间各向异性之间的相互作用引起的奇异的新兴量子激发和现象提供了一个可行的基础。然而，与它们的低自旋类似物不同，高自旋蜂窝晶格反铁磁体在捕捉量子现象的经典极限的背景下仍然相对较少被探索。在本文中，我们报告了 FeP3SiO11 多晶样品的晶体结构、磁化率、比热和电子自旋共振 （ESR） 测量，并辅以从头到位密度泛函理论 （DFT） 计算，其中 Fe3+ 离子装饰着近乎完美的 S=52蜂窝状晶格，组成原子之间没有任何位点无序。高于 150 K，观察到反铁磁 Weiss 温度 θCW=-12K，这与 DFT 计算一致，这表明存在较强的面内最近邻和较弱的面间远邻交换相互作用。TN=3.5K 的比热和磁化率异常揭示了零场中存在长程有序基态。在 TN 以上，ESR 证明了短程自旋相关性和不饱和磁熵，而在 TN 以下，通过幂律比热可以看到非常规激发。在 μ0Hc1=0.2 T 的外加区域观察到自旋-翻转转变。 在较高的应用领域，TN 在 μ0Hc2=5.6T 时逐渐被抑制到零。在 μ0Hc2 以上，由于间隙磁振子激发而导致的比热的宽最大值表明，在这种蜂窝状晶格反铁磁体中出现了一种有趣的近极化状态，其外衣是无序状态。