Magnetization distribution in the mixed-phase state of hole-doped manganites
Magnetization distribution in the mixed-phase state of hole-doped manganites
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DOI：
10.1038/nature01715
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发表时间：
2003-06-26
期刊：
影响因子：
64.8
通讯作者：
Kikuchi, M
中科院分区：
文献类型：
--
作者：
Murakami, Y;Yoo, JH;Kikuchi, M
空穴掺杂锰氧化物中的“巨磁阻”（CMR）效应--当施加磁场时电阻率的异常降低（1）--在过去十年中引起了研究人员的极大兴趣。但CMR现象的潜在机制尚未完全了解。已经清楚的是，相分离状态（2-6）是重要的，其中磁性相和非磁性相共存，但是这种混合相状态的详细磁性微观结构迄今为止还不清楚。在这里，我们使用电子显微镜研究的磁性显微结构和发展的铁磁畴的混合相态的La 1-xSrxMnO 3（x = 0.54，0.56）。我们的测量结果表明，在没有磁场的情况下，磁通量是封闭的铁磁区域内，这表明分离的铁磁畴之间的磁相互作用可以忽略不计。然而，我们也发现，只有很小的温度变化，域开始联合收割机。我们建议，微妙的性质的混合相态的空穴掺杂的锰氧化物的磁性微结构是负责CMR效应，其中显着的导电路径时，施加磁场的铁磁畴之间形成。
The effect of 'colossal magnetoresistance' (CMR) in hole-doped manganites - an abnormal decrease of resistivity when a magnetic field is applied(1) - has attracted significant interest from researchers in the past decade. But the underlying mechanism for the CMR phenomenon is not yet fully understood. It has become clear that a phase-separated state(2-6), where magnetic and nonmagnetic phases coexist, is important, but the detailed magnetic microstructure of this mixed-phase state is so far unclear. Here we use electron microscopy to study the magnetic microstructure and development of ferromagnetic domains in the mixed-phase state of La1-xSrxMnO3 (x = 0.54, 0.56). Our measurements show that, in the absence of a magnetic field, the magnetic flux is closed within ferromagnetic regions, indicating a negligible magnetic interaction between separated ferromagnetic domains. However, we also find that the domains start to combine with only very small changes in temperature. We propose that the delicate nature of the magnetic microstructure in the mixed-phase state of hole-doped manganites is responsible for the CMR effect, in which significant conduction paths form between the ferromagnetic domains upon application of a magnetic field.