Room temperature ferromagnetic (Ga,Mn)N epitaxial films with low Mn concentration grown by plasma-enhanced molecular beam epitaxy

Abstract

We report on the crystal structures, 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, exhibiting n-type conductivity and ferromagnetism with Curie temperature in the range 550-700 K. Transmission electron microscopy studies revealed that Mn ions substitute for Ga ions in the epitaxial structure, leading to the expansion of the lattice parameter a of the hexagonal (wurtzite) structure. The temperature dependence of the sheet resistance is found to show negative magnetoresistance in the temperature range 4-300 K, indicative of ferromagnetic semiconducting (Ga,Mn)N films. (C) 2002 Elsevier Science Ltd. All rights reserved.