Pseudogap Precursors in Optimal Doped EuBCO

For the pseudogap phase, an important feature of cuprate superconductivity, Varma et al. predict the existence of loop currents. By means of Maximum Entropy analysis, we investigate transverse field $\mu $SR data of optimal-doped EuBa$_{2}$Cu$_{3}$O$_{7-\delta}$ (T$_{\mathrm{c}} =$ 93 K). To search for precursor effects, and for predicted pseudogap loop currents, our focus is on a temperature interval between T$_{\mathrm{c}}$ and T*. An extra drop in normal-state frequency indicates demagnetization effects, possibly caused by short-living Cooper-pairs in the Cu-O$_{2}$ planes. In sum, our results suggest magnetic roots of cuprate superconductivity.