Ferromagnetic ordering of n-type (Ga,Mn)N epitaxial films

The magnetic and magnetotransport properties of epitaxial (Ga1-xMnx)N films with low Mn concentration (x=0.06-0.5%) grown by plasma-enhanced molecular beam epitaxy have been investigated. Ferromagnetic ordering for the GaMnN is clearly seen in the temperature range 4-300 K. The M-T curves were fitted with theoretical equations based on the mean field theory in order to estimate Curie temperature (T-c), providing T-c approximate to 550 K and T-c approximate to 700 K, respectively, for the (Ga,Mn)N films with x=0.16% and x=0.50%. Temperature dependence of sheet resistance is found to show negative magneto-resistance in the temperature range 4-300 K, indicative of ferromagnetic semiconducting (Ga,Mn)N films. (C) 2003 Elsevier B.V. All rights reserved.