The effects of nonmagnetic Al impurities on a magnetic bath ${\mathrm{YMnO}}_3$ are studied by magnetization, heat capacity, neutron diffraction, and NMR measurements. Suppression of the Néel order with an increase in the doping rate is evidenced by the heat capacity and $M\text{−}T$ curve, also showing vacancy-induced magnetization. Theory predicts that the vacancies in triangular antiferromagnets release the local frustration partially by a readjustment of the spin directions, which results in a net magnetic moment of $0.04S$ around the impurity site, where $S$ is the single spin moment. Interestingly, our NMR results show that the amplitude of the impurity moment is similar to $S$, which is one order of magnitude larger than a previous prediction. The direction of the impurity moment and neighboring spins generating a hyperfine field at a nonmagnetic impurity site are random. Above $T_N$, the release of frustration due to a spin-vacancy is evidenced by the enhancement of the antiferromagnetic correlation of spins near impurity sites. Based on careful consideration about the structural distortion, we suggest that this huge spin-disorder originates from the magnetic correlation between impurity moments.

中文翻译：

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受挫反铁磁体YMnO3中非磁性杂质附近的自旋无序状态

非磁性铝杂质对磁浴的影响 ${\mathrm{氧化锰}}_3$通过磁化，热容量，中子衍射和NMR测量来研究。热容和热能证明随着掺杂速率的增加，奈尔阶数的抑制。$\mathrm{中号}\text{-}Ť$曲线，还显示了空位诱导的磁化强度。理论预测，三角形反铁磁体中的空位会通过重新调整自旋方向来部分释放局部挫败感，从而导致净磁矩为$0.04\mathrm{小号}$ 在杂质位点附近 $\mathrm{小号}$是单旋转时刻。有趣的是，我们的NMR结果表明，杂质矩的幅度类似于$\mathrm{小号}$，比以前的预测大一个数量级。杂质矩的方向和在非磁性杂质位点产生超精细场的相邻自旋是随机的。以上${Ť}_{ñ}$，由于杂质位点附近的自旋的反铁磁相关性的增强，证明了由于自旋空位而产生的挫败感得以释放。基于对结构变形的仔细考虑，我们认为这种巨大的自旋失调源自杂质矩之间的磁相关。