Stabilization of ferromagnetic order in La(0.7)Sr(0.3)MnO3-SrRuO3 Superlattices.
Stabilization of ferromagnetic order in La(0.7)Sr(0.3)MnO3-SrRuO3 Superlattices.
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DOI：
10.1021/nl301963a
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发表时间：
2012-07
期刊：
影响因子：
10.8
通讯作者：
M. Ziese;F. Bern;E. Pippel;Dietrich Hesse;I. Vrejoiu
中科院分区：
文献类型：
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作者：
M. Ziese;F. Bern;E. Pippel;Dietrich Hesse;I. Vrejoiu
空间受限复合氧化物的研究受到广泛关注，因为界面处的关联电子可能形成奇异相。本文用结构技术、磁化强度和磁输运测量研究了具有共格生长界面的La（0.7）Sr（0.3）MnO（3）/SrRuO（3）超晶格。磁化强度测量表明，在La（0.7）Sr（0.3）MnO（3）层中的铁磁有序在超晶格中稳定到至少两个晶胞的层厚度。如果铁磁层被两个晶胞厚的SrTiO（3）层分开，则这种稳定性被破坏。超晶格的电阻率表现为金属性，并由导电的SrRuO（3）层控制，非对角电阻率表现为SrRuO（3）和La（0.7）Sr（0.3）MnO（3）层的反常霍尔效应。这表明La（0.7）Sr（0.3）MnO（3）层不仅是铁磁性的，而且是高导电的;可能在界面处诱导了导电空穴气，从而稳定了铁磁性有序。这一结果为制备具有长程铁磁有序的二维系统开辟了一条新的途径。
The study of spatially confined complex oxides is of wide interest, since correlated electrons at interfaces might form exotic phases. Here La(0.7)Sr(0.3)MnO(3)/SrRuO(3) superlattices with coherently grown interfaces were studied by structural techniques, magnetization, and magnetotransport measurements. Magnetization measurements showed that ferromagnetic order in ultrathin La(0.7)Sr(0.3)MnO(3) layers is stabilized in the superlattices down to layer thicknesses of at least two unit cells. This stabilization is destroyed, if the ferromagnetic layers are separated by two unit cell thick SrTiO(3) layers. The resistivity of the superlattices showed metallic behavior and was dominated by the conducting SrRuO(3) layers, the off-diagonal resistivity showed an anomalous Hall effect from both SrRuO(3) and La(0.7)Sr(0.3)MnO(3) layers. This shows that the La(0.7)Sr(0.3)MnO(3) layers are not only ferromagnetic but also highly conducting; probably a conducting hole gas is induced at the interfaces that stabilizes the ferromagnetic order. This result opens up an alternative route for the fabrication of two-dimensional systems with long-range ferromagnetic order.