Prospects for high temperature ferromagnetism in (Ga,Mn)As semiconductors

T. Jungwirth, K. Y. Wang, J. Mašek, K. W. Edmonds, Jürgen König, Jairo Sinova, M. Polini, N. A. Goncharuk, A. H. MacDonald, M. Sawicki, A. W. Rushforth, R. P. Campion, L. X. Zhao, C. T. Foxon, and B. L. Gallagher
Phys. Rev. B 72, 165204 – Published 13 October 2005

Abstract

We report on a comprehensive combined experimental and theoretical study of Curie temperature trends in (Ga,Mn)As ferromagnetic semiconductors. Broad agreement between theoretical expectations and measured data allows us to conclude that Tc in high-quality metallic samples increases linearly with the number of uncompensated local moments on MnGa acceptors, with no sign of saturation. Room temperature ferromagnetism is expected for a 10% concentration of these local moments. Our magnetotransport and magnetization data are consistent with the picture in which Mn impurities incorporated during growth at interstitial MnI positions act as double-donors and compensate neighboring MnGa local moments because of strong near-neighbor MnGaMnI antiferromagnetic coupling. These defects can be efficiently removed by post-growth annealing. Our analysis suggests that there is no fundamental obstacle to substitutional MnGa doping in high-quality materials beyond our current maximum level of 6.8%, although this achievement will require further advances in growth condition control. Modest charge compensation does not limit the maximum Curie temperature possible in ferromagnetic semiconductors based on (Ga,Mn)As.

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  • Received 9 May 2005

DOI:https://doi.org/10.1103/PhysRevB.72.165204

©2005 American Physical Society

Authors & Affiliations

T. Jungwirth1,2, K. Y. Wang2, J. Mašek3, K. W. Edmonds2, Jürgen König4, Jairo Sinova5, M. Polini6, N. A. Goncharuk1, A. H. MacDonald7, M. Sawicki8, A. W. Rushforth2, R. P. Campion2, L. X. Zhao2, C. T. Foxon2, and B. L. Gallagher2

  • 1Institute of Physics ASCR, Cukrovarnická 10, 162 53 Praha 6, Czech Republic
  • 2School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
  • 3Institute of Physics ASCR, Na Slovance 2, 182 21 Praha 8, Czech Republic
  • 4Institut für Theoretische Physik III, Ruhr-Universität Bochum, 44780 Bochum, Germany
  • 5Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA
  • 6NEST-INFM and Scuola Normale Superiore, I-56126 Pisa, Italy
  • 7Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
  • 8Institute of Physics, Polish Academy of Sciences, 02668 Warszawa, Poland

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Issue

Vol. 72, Iss. 16 — 15 October 2005

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