Formation of an antiferromagnetic metal phase in the electron-doped Sr$_{0.98}$La$_{0.02}$MnO$_3$ oxide according to $^{17}$O NMR data

The spin density distribution of itinerant electrons, $n_{eg}$, and their effect on pairwise correlations of localized spins $S(t_{2g})$ of Mn$^{4+}$ ions in cubic Sr$_{1-x}$La$_x$MnO$_3$ antiferromagnet ($x = 0.02$, $T_{\mathrm{N}} = 230$ K, $\mathrm{G}$ type magnetic structure) is studied experimentally by nuclear magnetic resonance on $^{17}$O nuclei. The regions with $n_{eg}>x$, in which the local spin susceptibility of pairs of Mn atoms follows the dependence $\chi\sim(T-\Theta)^{-1}$ with $\Theta = 20(5)$ K, indicating the growth of ferromagnetic spin correlations of neighboring magnetic ions in these domains, are found in the paramagnetic phase. The fraction of Mn-O-Mn bonds ($n_{eg}>x$) increases with the decrease in the temperature. The interpenetrating meshes of Mn-O-Mn bonds with different densities of itinerant $e_g$ electrons form an antiferromagnetic metal phase below $T_{\mathrm{N}}$. The role of weak localization effects is discussed as the main origin of the magnetic inhomogeneity of the antiferromagnetic metal phase in Sr$_{0.98}$La$_{0.02}$MnO$_3$.