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Transition between two ferromagnetic states driven by orbital ordering in La_{0.88}Sr_{0.12}MnO_3

Y. Endoh·K. Hirota·S. Ishihara·S. Okamoto·Y. Murakami·A. Nishizawa·T. Fukuda·H. Kimura·H. Nojiri·K. Kaneko·S. Maekawa
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Abstract

A lightly doped perovskite mangantite La_{0.88}Sr_{0.12}MnO_3 exhibits a phase transition at T_{OO}=145 K from a ferromagnetic metal (T_C=172 K) to a novel ferromagnetic insulator.We identify that the key parameter in the transition is the orbital degree of freedom in e_g electrons. By utilizing the resonant x-ray scattering technique, orbital ordering is directly detected below T_{OO}, in spite of a significant diminution of the cooperative Jahn-Teller distortion. The new experimental features are well described by a theory treating the orbital degree of freedom under strong electron correlation. The present experimental and theoretical studies uncover a crucial role of the orbital degree in the metal-insulator transition in lightly doped manganites.

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Y. Endoh, K. Hirota, S. Ishihara, S. Okamoto, Y. Murakami, A. Nishizawa, T. Fukuda, H. Kimura, H. Nojiri, K. Kaneko, S. Maekawa. 1999-01-16. Transition between two ferromagnetic states driven by orbital ordering in La_{0.88}Sr_{0.12}MnO_3. https://doi.org/10.1103/physrevlett.82.4328

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