Impact of Charge Ordering on Magnetic Correlations in Perovskite (Bi,Ca)MnO3
نویسندگان
چکیده
Single crystalline Bi1−xCaxMnO3 (0.74 ≤ x ≤ 0.82) were studied with neutron scattering, electron diffraction and bulk magnetic measurement. We discovered dynamic ferromagnetic spin correlations at high temperatures, which are replaced by antiferromagnetic spin fluctuations at a concomitant charge ordering and structural transition. Our results indicate that thermal-activated hopping of the Jahn-Teller active eg electrons in these insulating materials, nevertheless, induce ferromagnetic interaction through double-exchange mechanism. It is the ordering of these charges competing with the doubleexchange ferromagnetic metallic state. Typeset using REVTEX
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