Observation of ferromagnetism and anomalous Hall effect in laser-deposited chromium-doped indium tin oxide films

We report on the structural, magnetic, and magnetotran sport characteristics of Cr-cloped indium tin oxide (ITO) films grown on SiO2/Si substrates by pulsed laser deposition. Structural analysis clearly indicates that homogeneous films of bixbyite structure are grown without any detectable formation of secondary phases up to 20 mol% Cr doping. The carrier concentration is found to decrease with Cr ion addition, displaying a change in the conduction type from n-type to p-type around 15 mol% Cr doping. Room temperature ferromagnetism is observed, with saturation magnetization of similar to 0.7 emu/cm(3), remnant magnetization of similar to 0.2 emu/cm(3) and coercive field of similar to 30 Oe for 5 mol% Cr-doped ITO. Magnetotransport measurements reveal the unique feature of diluted magnetic semi conductors, in particular, an anomalous Hall effect governed by electron doping, which indicates the intrinsic nature of ferromagnetism in Cr-doped ITO. These results suggest that Cr-doped ITO could be promising for semiconductor spin electronics devices. (c) 2005 Elsevier Ltd. All rights reserved.