Pb1-2y/3LayZrxTi1-xO3 (PLZT) thin films have been prepared "in situ'' by multi-target sputtering on Silicon, LaAlO3 (LAO) and MgO substrates covered with a Pt bottom electrode. The purpose was to grow tetragonal PLZT films (Zr/Ti = 28/72 with different La contents) on these various substrates and to compare their electrical properties. To this aim, Pt was first deposited on the three different substrates to get (1 1 1) Pt/Si, (1 1 1) Pt/LAO and (2 0 0) Pt/MgO. Then PLZT was deposited in a same run on these three kinds of substrates and the influence of La contents and film orientation on electrical properties was investigated. The La content was varied from y = 0 to y = 32 in order to explore the phase transition between ferroelectric and paraelectric phases as a function of the substrate. For large amount of Lanthanum, relaxor behavior has been observed and studied. (C) 2007 Elsevier B.V. All rights reserved.