Toyosaki Hidemi, Fukumura Tomoteru, Yamada Yasuhiro, Nakajima Kiyomi, Chikyow Toyohiro, Hasegawa Tetsuya, Koinuma Hideomi, Kawasaki Masashi
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Nat Mater. 2004 Apr;3(4):221-4. doi: 10.1038/nmat1099. Epub 2004 Mar 21.
Ferromagnetic semiconductors are believed to be suitable for future spintronics, because both charge and spin degrees of freedom can be manipulated by external stimuli. One of the most important characteristics of ferromagnetic semiconductors is the anomalous Hall effect. This is because the ferromagnetically spin-polarized carrier can be probed and controlled electrically, leading to direct application for electronics. Control of the Curie temperature and magnetization direction by electronic field, and photo-induced ferromagnetism have been performed successfully using the anomalous Hall effect for group III-V ferromagnetic semiconductors. In these cases, the operation temperature was much below room temperature because of the limited Curie temperature of less than 160 K (ref. 6). Here, we report on the anomalous Hall effect governed by electron doping in a room-temperature transparent ferromagnetic semiconductor, rutile Ti(1-x)Co(x)O(2-delta) (of oxygen deficiency delta). This result manifests the intrinsic nature of ferromagnetism in this compound, and represents the possible realization of transparent semiconductor spintronics devices operable at room temperature.
铁磁半导体被认为适用于未来的自旋电子学，因为电荷和自旋自由度都可以通过外部刺激进行操控。铁磁半导体最重要的特性之一是反常霍尔效应。这是因为铁磁自旋极化载流子可以通过电学方法进行探测和控制，从而直接应用于电子学领域。利用反常霍尔效应，针对III-V族铁磁半导体，已经成功实现了通过电场控制居里温度和磁化方向，以及光致铁磁性。在这些情况下，由于居里温度有限，低于160 K（参考文献6），操作温度远低于室温。在此，我们报道了在室温透明铁磁半导体金红石型Ti(1-x)Co(x)O(2-δ)（存在氧缺陷δ）中由电子掺杂控制的反常霍尔效应。这一结果揭示了该化合物中铁磁性的内在本质，并代表了在室温下可操作的透明半导体自旋电子器件的可能实现。
