Behavior of Mn3+ ions in four-layered hexagonal (Sr1−x−yLaxBay)MnO3

Stoichiometric four-layered hexagonal (4H) (Sr1−x−yBaxLay)MnO3 was synthesized using a standard ceramic technique. Rietveld analysis at room temperature indicated that the Mn–O(1) distance increased and the Mn–O(2) distance decreased with the increase in x. The samples were n-type semiconductors and exhibited hopping conductivity in a small-polaron model below 533 K. The Mn3+ ion acted as a donor and the electron transfer became active through the Mn3+–O–Mn4+ path. The samples were antiferromagnetic and the Néel temperature (TN) was constant regardless of y when x was fixed to 0.3, whereas TN shifted to a high temperature when y was fixed to 0.02. The face-sharing Mn3+–O(2)–Mn4+ interaction strengthened as the Mn–O(2) distance decreased, and TN shifted to a high temperature as a result.

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