Multilayers of (1-x) Pb (Mg13 Nb23) O3 -x PbTiO3 thin films were prepared with a compositional variation of PbTiO3 on each layer across the film by pulsed laser ablation technique. The fabricated films were found to possess an enhanced diffusiveness in the dielectric phase transition, which actually seemed to be an envelope of the phase transition of the individual layer relaxor ferroelectrics of a particular composition. They also showed a very high nonlinear dielectric response and hence a high tunability about 70%, an increase of about 40% than that observed for single layer composition. This increase in tunability has been attributed to the lattice strain and the artificially enhanced chemical heterogeneity of the system. These multilayer films also showed a slim hysteresis loop characteristic with a saturation and remnant polarization of 20 and 6 μC cm2, respectively. © 2005 American Institute of Physics.