X-Ray Emission Studies of Evolution of the Electron
and Spin Structures of Mn in Mixed Manganites Ln_1xSr_xMnO₃
(Ln = La, Sm, and Ce)

A. E. Sovestnov^a, *, B. T. Melekh^b, V. V. Fedorov^{a, c}, and E. V. Fomin^a

^a Konstantinov Petersburg Nuclear Physics Institute, Russian Academy of Sciences,
Orlova Roshcha, Gatchina, Leningrad oblast, 188300 Russia

*e-mail: asovest@pnpi.spb.ru

^b Ioffe Physical-Technical Institute, Russian Academy of Sciences,
Politekhnicheskaya ul. 26, St. Petersburg, 194021 Russia

^c St. Petersburg State Polytechnical University,
Politekhnicheskaya ul. 29, St. Petersburg, 195251 Russia

Received July 19, 2011; in final form, September 30, 2011

Abstract—The chemical shift and the exchange splitting E_split of the emission X-ray Mn K₁ line in
mixed manganites Ln_1–xSr_xMnO₃ (Ln = La, Sm, and Ce) have been systematically studied for the first time. It
has been found that and E_split are almost the same in the range x < 0.4–0.5, as is the case in Mn₂O₃, and
then they decrease relatively quickly to the values characteristic of MnO₂. It has been assumed that such a
behavior corresponds to the model where in the region of hole doping (x < 0.5), the ground state is a mixture
of configurations Mn³⁺ 3d⁴ and , so that the second configuration fraction increases with x. At high values
of x, the configuration Mn⁴⁺ 3d³ should be taken into account; the contribution of this configuration increases
with increasing degree of doping, and it becomes dominant at x = 1. In all cases, the manganese state is high-
spin.

DOI: 10.1134/S1063783412040282

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