Observation of a low Curie temperature ferromagnetic phase of ultrathin epitaxial Fe films on GaAs(0 0 1)
Observation of a low Curie temperature ferromagnetic phase of ultrathin epitaxial Fe films on GaAs(0 0 1)
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GaAs(0 0 1) 上超薄外延 Fe 薄膜低居里温度铁磁相的观察
DOI：
10.1016/j.jmmm.2004.10.117
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Hopkinson
中科院分区：
文献类型：
--
作者：
M. Spangenberg;J. Neal;T. Shen;S. Morton;J. Tobin;G. D. Waddill;J. Matthew;D. Greig;A. Malins;E. Seddon;M. Hopkinson
在最初的几个单分子层范围内，在GaAs上生长的Fe外延薄膜的磁性是近年来大量研究的主题。在室温下没有磁性特征被归因于磁性“死层”的存在以及超顺磁性的存在。通过研究铁心能级光电子的磁线性二向色性随温度的变化，我们发现了一个铁磁性区域，其居里温度Tc远低于室温，例如，对于名义厚度为0.9 nm的薄膜，Tc约为240K。居里温度对初始的衬底条件很敏感，Fe覆盖层的厚度为1.25 nm，表现出高于室温的温度。这些数据表明，尽管薄膜中的交换作用较弱，导致居里温度显著降低，但在生长的早期阶段，在GaAs(001)上的薄膜可能具有铁磁性。
The magnetic properties of epitaxial Fe films on GaAs in the range of the first few monolayers have been the subject of a considerable number of investigations in recent years. The absence of magnetic signatures at room temperature has been attributed to the existence of a magnetic ‘dead’ layer as well as superparamagnetism. By examining the temperature dependence of the magnetic linear dichroism of the Fe core level photoelectrons, we found a ferromagnetic regime with a Curie temperature, Tcsubstantially lower than room temperature, e.g., a Tcof about 240K for thin films of a nominal thickness of 0.9nm. The values of Curie temperature were sensitive to the initial GaAs substrate conditions and the thickness of the Fe over-layer with a layer of thickness of 1.25nm showing a Tcabove room temperature. The data suggest that the thin Fe films on GaAs(001) may have ferromagnetic character at an earlier stage of growth than previously expected, although a weaker exchange interaction in the films leads to a substantial reduction in Curie temperature.
影响因子：
8.6
作者：
Kikkawa, JM;Awschalom, DD
通讯作者：
Awschalom, DD