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Anomalous Hall effect governed by electron doping in a room-temperature transparent ferromagnetic semiconductor

Nature Materials volume 3, pages 221224 (2004) | Download Citation



Ferromagnetic semiconductors are believed to be suitable for future spintronics, because both charge and spin degrees of freedom1,2 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 temperature3 and magnetization direction4 by electronic field, and photo-induced ferromagnetism5 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 Ti1–xCoxO2–δ (of oxygen deficiency δ). 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.

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This work was supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology in Japan, Grant-in-Aid for Creative Scientific Research (14GS0204 an 13NP0201), NEDO International Joint Research program (02BR3) and the Inamori Foundation.

Author information


  1. Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan

    • Hidemi Toyosaki
    • , Tomoteru Fukumura
    • , Yasuhiro Yamada
    •  & Masashi Kawasaki
  2. National Institute for Materials Science, Tsukuba 305-0044, Japan

    • Kiyomi Nakajima
    •  & Toyohiro Chikyow
  3. Combinatorial Materials Exploration and Technology, Tsukuba 305-0044, Japan

    • Kiyomi Nakajima
    • , Toyohiro Chikyow
    • , Tetsuya Hasegawa
    • , Hideomi Koinuma
    •  & Masashi Kawasaki
  4. Department of Chemistry, University of Tokyo, Tokyo 113-0033, Japan

    • Tetsuya Hasegawa
  5. Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan

    • Hideomi Koinuma


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Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Tomoteru Fukumura.

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