We present the microstructure, phase stability, magnetic, transport and optical properties of Ni-25 at.%Al alloy thin films, which were deposited from a target of the intermetallic compound Ni3Al onto the oxidized Si substrates at two different temperatures: 45 and 400degreesC. The microstructure of these films was characterized by the transmission electron microscopy. Whereas the films deposited at 45degreesC were chemically disordered in the as-deposited condition and consisted of fcc as well as hcp phases; those deposited at elevated temperatures (400degreesC) were chemically ordered and exhibited the Ll(2) type ordering characteristic of the intermetallic compound Ni3Al. Both the films exhibited a weak itinerant ferromagnetism, the T-C of the chemically ordered film deposited at 400degreesC being substantially higher than that of the disordered film deposited at 45degreesC. Electrical transport measurements indicated that both films were good conductors whose four-point probe resistivity data had only a weak temperature dependence. The optical reflectance of the film deposited at 45degreesC was lower than that of the film deposited at 400degreesC for the entire range of wavelengths measured. (C) 2003 Elsevier B.V. All rights reserved.