Pulsed laser deposition (PLD) was used to prepare substitutionaly disordered Pt3Sc. Deposition was performed by using a crossed-beam PLD setup and the laser intensity on the Pt and Sc targets was adjusted to reach the desired composition (Pt:Sc 3:1). Deposition was performed in vacuum, 133 Pa He and 133 Pa Ar, on both Cu and Si substrates. It was shown that a homogeneous and substitutionaly disordered Pt3Sc alloy is formed when deposition is performed in vacuum and 133 Pa Ar on a Cu substrate. Alternatively, a non-homogeneous and multilayered deposit is formed when deposition is performed in vacuum on a Si substrate. This is believed to arise as a consequence of re-sputtering (and decomposition) of the native silicon oxide when highly energetic ablated species impinge on the substrate. The kinetic energy of the ablated species is reduced by increasing the pressure of Ar in the deposition chamber, yielding to an increased stability of the native silicon oxide layer and the formation of a porous deposit made of substitutionaly disordered Pt3Sc. The same phenomenon is observed when deposition is performed on a Ti substrate. (C) 2012 Elsevier B. V. All rights reserved.