High-Curie-temperature ferromagnetism in self-organized Ge1-xMnx nanocolumns
High-Curie-temperature ferromagnetism in self-organized Ge1-xMnx nanocolumns
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DOI：
10.1038/nmat1686
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发表时间：
2006-08-01
期刊：
影响因子：
41.2
通讯作者：
Tatarenko, Serge
中科院分区：
文献类型：
--
作者：
Jamet, Matthieu;Barski, Andre;Tatarenko, Serge
如果能在与硅技术兼容的半导体纳米结构中加入室温铁磁性，新兴的自旋电子学领域将得到极大的推动。本文报道了（Ge，Mn）外延层的高温（> 400 K）铁磁相。锰含量为6%，仔细的结构和化学分析表明，锰的分布是非常不均匀的：我们观察到共析生长的定义良好的富锰纳米柱周围的锰贫矩阵。这些纳米柱的平均直径为3 nm，间距为10 nm。它们的成分接近Ge 2 Mn，对应于未知的富锗相，并且它们具有单轴伸长的金刚石结构。它们的居里温度高于400 K。磁输运揭示了一个明显的反常霍尔效应，室温。在30 K和9 T下测量到从7,000%到200%的巨正磁阻，没有饱和的迹象。
The emerging field of spintronics would be dramatically boosted if room-temperature ferromagnetism could be added to semiconductor nanostructures that are compatible with silicon technology. Here, we report a high-TC (> 400 K) ferromagnetic phase of (Ge, Mn) epitaxial layer. The manganese content is 6%, and careful structural and chemical analyses show that the Mn distribution is strongly inhomogeneous: we observe eutectoid growth of well-defined Mn-rich nanocolumns surrounded by a Mn-poor matrix. The average diameter of these nanocolumns is 3 nm and their spacing is 10nm. Their composition is close to Ge2Mn, which corresponds to an unknown germanium-rich phase, and they have a uniaxially elongated diamond structure. Their Curie temperature is higher than 400 K. Magnetotransport reveals a pronounced anomalous Hall effect up to room temperature. A giant positive magnetoresistance is measured from 7,000% at 30K to 200% at 300K and 9 T, with no evidence of saturation.