Impact of charge ordering on magnetic correlations in perovskite (Bi,Ca)MnO3
Impact of charge ordering on magnetic correlations in perovskite (Bi,Ca)MnO3
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DOI：
10.1103/physrevlett.78.543
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发表时间：
1997-01-20
影响因子：
8.6
通讯作者：
Cheong, SW
中科院分区：
文献类型：
--
作者：
Bao, W;Axe, JD;Cheong, SW
用中子散射、电子衍射和体磁测量研究了Bi_（1-x）Ca_xMnO_3（0.74 ≤ x ≤ 0.82）单晶。我们发现在高温下的动态铁磁自旋相关，这是由反铁磁自旋波动在伴随的电荷有序和结构转变所取代。我们的结果表明，这些绝缘材料中Jahn-Teller活性e（g）电子的热激活跳跃，通过双交换机制诱导铁磁相互作用。正是这些电荷的有序性与双交换铁磁金属态竞争。
Single crystalline Bi1-xCaxMnO3 (0.74 less than or equal to x less than or equal to 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 e(g) electrons in these insulating materials, nevertheless, induces ferromagnetic interaction through; the double-exchange mechanism. It is the ordering of these charges which competes with the double-exchange ferromagnetic metallic state.