Ferromagnetic nitride-based semiconductors doped with transition metals and rare earths
Ferromagnetic nitride-based semiconductors doped with transition metals and rare earths
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DOI：
10.1088/0268-1242/22/9/r01
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发表时间：
2007-09
影响因子：
1.9
通讯作者：
A. Bonanni
中科院分区：
文献类型：
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作者：
A. Bonanni
本文综述了基于过渡金属和稀土掺杂氮化物的室温铁磁半导体的研究进展。报告了主要的合成方法，并概述了材料系统的磁性、结构、电学和光学特性。强调了有关磁掺杂氮化物中居里温度实际值的有争议的实验结果，证明了标准表征方法的不足，并强调了对系统进行可能详尽的结构研究的必要性。此外，还讨论了磁性离子掺入半导体基体的制备参数的依赖性，特别注意了溶解度极限和旋量分解的基本概念。本文认为，磁掺杂氮化物的高温铁磁特性是由于含有高浓度磁性成分的纳米级区域的存在。列出了这些多组件系统的各种功能。此外，我们还对氮化物基体中单一磁性杂质态的性质进行了广泛的概述。当考虑到通过费米水平工程来控制磁离子分布以及磁响应的最新建议，以及在包含均匀分布的磁离子的系统中实现高温铁磁性的道路时，对这一限制的理解是至关重要的。
This review summarizes the state-of-the-art in the search for room temperature ferromagnetic semiconductors based on transition-metal- and rare-earth-doped nitrides. The major methods of synthesis are reported, together with an overview of the magnetic, structural, electrical and optical characterization of the materials systems, where available. The controversial experimental results concerning the actual value of the apparent Curie temperature in magnetically doped nitrides are highlighted, the inadequacy of standard characterization methods alone and the necessity of a possibly exhaustive structural investigation of the systems are proven and underlined. Furthermore, the dependence on the fabrication parameters of the magnetic ions incorporation into the semiconductor matrix is discussed, with special attention to the fundamental concepts of solubility limit and spinodal decomposition. It is argued that high-temperature ferromagnetic features in magnetically doped nitrides result from the presence of nanoscale regions containing a high concentration of the magnetic constituents. Various functionalities of these multicomponent systems are listed. Moreover, we give an extensive overview on the properties of single magnetic-impurity states in the nitride host. The understanding of this limit is crucial when considering the most recent suggestions for the control of the magnetic ion distribution—and consequently of the magnetic response—through the Fermi level engineering as well as to indicate roads for achieving high-temperature ferromagnetism in the systems containing a uniform distribution of magnetic ions.