Films of mixed nickel-tungsten oxide, denoted Ni(x)W(1-x) oxide, were prepared by reactive DC magnetron co-sputtering from metallic targets and were characterized by Rutherford backscattering spectrometry. X-ray photoelectron spectroscopy, X-ray diffractometry and Raman spectroscopy. A consistent picture of the structure and composition emerged, and at x<0.50 the films comprised a mixture of amorphous WO(3) and nanosized NiWO(4), at x = 0.50 the nanosized NiWO(4) phase was dominating, and at x>0.50 the films contained nanosized NiO and NiWO(4). (C) 2010 Elsevier B.V. All rights reserved.