We present a ${}^{75}\mathrm{As}$ nuclear magnetic resonance (NMR) and resistivity study of the effect of 5.5 MeV proton irradiation on the optimal electron doped $\left(x=0.068\right)$ and overdoped $\left(x=0.107\right)$ $\mathrm{Ba}{\left({\mathrm{Fe}}_{1-x}{\mathrm{Rh}}_x\right)}_2{\mathrm{As}}_2$ iron based superconductors. While the proton induced defects only mildly suppress the critical temperature and increase residual resistivity in both compositions, sizable broadening of the NMR spectra was observed in all the irradiated samples at low temperature. The effect is significantly stronger in the optimally doped sample where the Curie Weiss temperature dependence of the line width suggests the onset of ferromagnetic correlations coexisting with superconductivity at the nanoscale. $1/T_2$ measurements revealed that the energy barrier characterizing the low energy spin fluctuations of these compounds is enhanced upon proton irradiation, suggesting that the defects are likely slowing down the fluctuations between $(0,\pi )$ and $(\pi$,0) nematic ground states.

中文翻译：

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质子辐照对Ba（Fe1-xRhx）2As2超导体常态低能激发的影响

我们提出一个 ${}^{75}\mathrm{作为}$ 5.5 MeV质子辐照对最佳掺杂电子的影响的核磁共振（NMR）和电阻率研究 $（X=0.068）$ 并过度掺杂 $（X=0.107）$ $巴{（{铁}_{\mathrm{1个}-X}{铑}_X）}_{\mathrm{2个}}{\mathrm{作为}}_{\mathrm{2个}}$铁基超导体。虽然质子诱导的缺陷仅温和地抑制了临界温度并增加了两种组合物中的残余电阻率，但在低温下所有被辐照的样品中均观察到NMR光谱相当大的展宽。在最佳掺杂的样品中，该效应明显更强，其中线宽的居里·魏斯温度依赖性表明在纳米级与超导共存的铁磁相关性的开始。$\mathrm{1个}/{Ť}_{\mathrm{2个}}$ 测量表明，质子辐照增强了表征这些化合物低能自旋涨落的能垒，这表明缺陷可能减缓了这些化合物之间的涨落。 $（0，\pi ）$ 和 $（\pi$，0）向列基态。