The effect of Mg doping on the dielectric and tunable properties of Pb 0.3Sr0.7TiO3 thin films prepared by sol-gel method

Abstract

Mg doped Pb0.3Sr0.7TiO3 (PST) thin films were fabricated by the sol-gel method on a Pt/Ti/SiO2/Si substrate. The microstructure, surface morphology, dielectric and tunable properties of PST thin films were investigated as a function of Mg concentration. It is found that proper Mg doping dramatically improves the dielectric loss (0.0088 @ 1 MHz), furthermore, the crystallinity, dielectric constant, and tunability of films simultaneously decrease with the increase of Mg content. The 2 mol% Mg doped PST thin film shows the highest figure of merit (FOM) value of 36.8 for its the smallest dielectric loss and upper tunability. The dependence of Rayleigh coefficient on the doping concentration was examined, which indicated that the reduction of dielectric constant and tunability of films should be related to the \mathrm{Mg}''-{\mathrm{Ti}} - \mathrm{V}-{\mathrm{O}}^{\bullet\ bullet} defect dipoles pinning the domain wall motion of residual polar clusters in PST. © 2013 The Author(s).