Article abstract
Nature Materials 2, 673 - 677 (2003)
Published online: 21 September 2003 | doi:10.1038/nmat984
Subject Categories: Semiconductors | Magnetic materials
Ferromagnetism above room temperature in bulk and transparent thin films of Mn-doped ZnO
Parmanand Sharma1,7, Amita Gupta1, K. V. Rao1, Frank J. Owens2, Renu Sharma3, Rajeev Ahuja4, J. M. Osorio Guillen4, Börje Johansson4,5 & G. A. Gehring6
Abstract
The search for ferromagnetism above room temperature in dilute magnetic semiconductors has been intense in recent years. We report the first observations of ferromagnetism above room temperature for dilute (<4 at.%) Mn-doped ZnO. The Mn is found to carry an average magnetic moment of 0.16 
B per ion. Our ab initio calculations find a valance state of Mn2+ and that the magnetic moments are ordered ferromagnetically, consistent with the experimental findings. We have obtained room-temperature ferromagnetic ordering in bulk pellets, in transparent films 2–3 m thick, and in the powder form of the same material. The unique feature of our sample preparation was the low-temperature processing. When standard high-temperature (T > 700 °C) methods were used, samples were found to exhibit clustering and were not ferromagnetic at room temperature. This capability to fabricate ferromagnetic Mn-doped ZnO semiconductors promises new spintronic devices as well as magneto-optic components.
- Department of Materials Science-Tmfy-MSE, Royal Institute of Technology, SE 10044 Stockholm, Sweden
- Armament Research, Development and Engg Ctr, Picatinny, New Jersey 07806, USA
- Center for Solid State Sciences, Arizona State University, Tampe, Arizona 85287-1704, USA
- Condensed Matter Theory Group, Department of Physics, University of Uppsala, Box 530, SE 75121 Uppsala, Sweden
- Applied Materials Physics, Department of Materials Science, Royal Institute of Technology, SE 10044 Stockholm, Sweden
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
- Currently at: Institute of Materials Research, Tohoku University, Sendai, 980-8577 Japan
Correspondence to: K. V. Rao1 e-mail: rao@kth.se
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