Article abstract


Nature Materials 5, 298 - 304 (2006)
doi:10.1038/nmat1613

Subject Categories: Semiconductors | Magnetic materials

Carrier-controlled ferromagnetism in transparent oxide semiconductors

J. Philip1, A. Punnoose2, B. I. Kim2, K. M. Reddy2, S. Layne1, J. O. Holmes2, B. Satpati3, P. R. LeClair1,4, T. S. Santos1 and J. S. Moodera1


The search for an ideal magnetic semiconductor with tunable ferromagnetic behaviour over a wide range of doping or by electrical gating is being actively pursued as a major step towards realizing spin electronics. A magnetic semiconductor having a high Curie temperature, capable of independently controlled carrier density and magnetic doping, is crucial for developing spin-based multifunctional devices. Cr-doped In2O3 is such a unique system, where the electrical and magnetic behaviour—from ferromagnetic metal-like to ferromagnetic semiconducting to paramagnetic insulator—can be controllably tuned by the defect concentration. An explicit dependence of magnetic interaction leading to ferromagnetism on the carrier density is shown. A carrier-density-dependent high Curie temperature of 850–930 K has been measured, in addition to the observation of clear magnetic domain structures in these films. Being optically transparent with the above optimal properties, Cr-doped In2O3 emerges as a viable candidate for the development of spin electronics.

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  1. Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
  2. Department of Physics, Boise State University, Boise, Idaho 83725, USA
  3. Institute of Physics, Sachivalaya Marg, Bhuvaneswar 751005, India
  4. Present address: Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487, USA

Correspondence to: J. Philip1 e-mail: jphilip@mit.edu

Correspondence to: J. S. Moodera1 e-mail: moodera@mit.edu

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