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 2 g ) of Mn 4+ ions in cubic Sr 1 − x La x MnO 3 antiferromagnet ( x = 0.02, T N = 230 K, 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 χ ∼ ( T − Θ) −1 with Θ = 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 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 .