Article abstract


Nature Materials 6, 440 - 446 (2007)
Published online: 21 May 2007 | doi:10.1038/nmat1910

Subject Categories: Electronic materials | Semiconductors | Magnetic materials

Origin and control of high-temperature ferromagnetism in semiconductors

Shinji Kuroda1, Nozomi Nishizawa1, Kôki Takita1, Masanori Mitome2, Yoshio Bando2, Krzysztof Osuch3,4 & Tomasz Dietl5,6


The extensive experimental and computational search for multifunctional materials has resulted in the development of semiconductor and oxide systems, such as (Ga,Mn)N, (Zn,Cr)Te and HfO2, which exhibit surprisingly stable ferromagnetic signatures despite having a small or nominally zero concentration of magnetic elements. Here, we show that the ferromagnetism of (Zn,Cr)Te, and the associated magnetooptical and magnetotransport functionalities, are dominated by the formation of Cr-rich (Zn,Cr)Te metallic nanocrystals embedded in the Cr-poor (Zn,Cr)Te matrix. Importantly, the formation of these nanocrystals can be controlled by manipulating the charge state of the Cr ions during the epitaxy. The findings provide insight into the origin of ferromagnetism in a broad range of semiconductors and oxides, and indicate possible functionalities of these composite systems. Furthermore, they demonstrate a bottom-up method for self-organized nanostructure fabrication that is applicable to any system in which the charge state of a constituent depends on the Fermi-level position in the host semiconductor.

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  1. Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
  2. Advanced Materials and Nanomaterials Laboratories, National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
  3. Faculty of Physics, Warsaw University of Technology, Koszykowa 75, PL 00-662 Warszawa, Poland
  4. Department of Physics, University of South Africa, PO Box 392, Pretoria 0003, South Africa
  5. Laboratory for Cryogenic and Spintronic Research, Institute of Physics, Polish Academy of Sciences, and ERATO Semiconductor Spintronics JST Project, al. Lotników 32/46, PL 02-668 Warszawa, Poland
  6. Institute of Theoretical Physics, Warsaw University, PL 00-681 Warszawa, Poland

Correspondence to: Shinji Kuroda1 e-mail: kuroda@ims.tsukuba.ac.jp

Correspondence to: Tomasz Dietl5,6 e-mail: dietl@ifpan.edu.pl

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