We report a comprehensive muon spin rotation ($\mu \mathrm{SR}$) study of the prototypical magnetoelectric antiferromagnet ${\mathrm{Cr}}_2{\mathrm{O}}_3$. We find the positively charged muon (${\mu }^{+}$) occupies several distinct interstitial sites and displays a rich dynamic behavior involving local hopping, thermally activated site transitions, and the formation of a charge-neutral complex composed of a muon and an electron polaron. The discovery of such a complex has implications for the interpretation of $\mu \mathrm{SR}$ spectra in a wide range of magnetic oxides and opens a route to study the dopant characteristics of interstitial hydrogen impurities in such materials. We address implications arising from implanting a ${\mu }^{+}$ into a linear magnetoelectric and discuss the challenges of observing a local magnetoelectric effect generated by the charge of the muon.

中文翻译：

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反铁磁Cr2O3中电荷中性的Muon-Polaron配合物的观察

我们报告了全面的介子自旋旋转（$\mu \mathrm{SR}$原型磁电反铁磁体的研究 ${铬}_2{\mathrm{Ø}}_3$。我们发现带正电荷的介子（${\mu }^{+}$）占据了几个不同的间隙位点，并显示出丰富的动力学行为，包括局部跳跃，热激活的位点跃迁以及由介子和电子极化子组成的电荷中性复合物的形成。这种复合物的发现对解释$\mu \mathrm{SR}$在广泛的磁性氧化物中进行光谱分析，为研究此类材料中间隙氢杂质的掺杂特性开辟了一条途径。我们将解决因植入${\mu }^{+}$ 成线性磁电，并讨论了观察由介子电荷产生的局部磁电效应的挑战。